diff --git a/backend/models.py b/backend/models.py
index 10bce63..94af965 100644
--- a/backend/models.py
+++ b/backend/models.py
@@ -239,6 +239,21 @@ class Attachment(Base):
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)
 
 
+class Memo(Base):
+    __tablename__ = "memos"
+    __table_args__ = (
+        Index("ix_memos_user_deleted_updated", "user_id", "deleted_at", "updated_at", "id"),
+    )
+    id: Mapped[UUID] = mapped_column(primary_key=True, default=new_id)
+    user_id: Mapped[UUID] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), index=True)
+    title: Mapped[str] = mapped_column(String(200))
+    content: Mapped[str] = mapped_column(Text, default="")
+    version: Mapped[int] = mapped_column(Integer, default=1)
+    created_at: Mapped[datetime] = mapped_column(UTCDateTime(), default=utcnow)
+    updated_at: Mapped[datetime] = mapped_column(UTCDateTime(), default=utcnow)
+    deleted_at: Mapped[datetime | None] = mapped_column(UTCDateTime(), nullable=True)
+
+
 class AuditLog(Base):
     __tablename__ = "audit_logs"
     id: Mapped[UUID] = mapped_column(primary_key=True, default=new_id)
diff --git a/backend/mvp.py b/backend/mvp.py
index 12bfd0a..3ad4847 100644
--- a/backend/mvp.py
+++ b/backend/mvp.py
@@ -32,6 +32,7 @@ from .models import (
     Habit,
     HabitLog,
     HabitPause,
+    Memo,
     RecurrenceException,
     RecurrenceTemplate,
     Task,
@@ -48,6 +49,172 @@ def audit(db: AsyncSession, user_id: UUID, action: str, entity_type: str, entity
     db.add(AuditLog(user_id=user_id, action=action, entity_type=entity_type, entity_id=entity_id, details=details))
 
 
+class MemoCreate(BaseModel):
+    title: str = Field(min_length=1, max_length=200)
+    content: str = ""
+
+    @field_validator("title", mode="before")
+    @classmethod
+    def clean_title(cls, value: str) -> str:
+        return value.strip()
+
+
+class MemoUpdate(BaseModel):
+    title: str | None = Field(default=None, min_length=1, max_length=200)
+    content: str | None = None
+    version: int = Field(ge=1)
+
+    @field_validator("title", mode="before")
+    @classmethod
+    def clean_title(cls, value: str | None) -> str | None:
+        if value is None:
+            return value
+        return value.strip()
+
+    @model_validator(mode="after")
+    def reject_nulls(self):
+        for field in ("title", "content"):
+            if field in self.model_fields_set and getattr(self, field) is None:
+                raise ValueError(f"{field} cannot be null")
+        return self
+
+
+class MemoOut(BaseModel):
+    model_config = {"from_attributes": True}
+    id: UUID
+    title: str
+    content: str
+    version: int
+    created_at: datetime
+    updated_at: datetime
+    deleted_at: datetime | None
+
+
+class MemoListItem(BaseModel):
+    id: UUID
+    title: str
+    excerpt: str
+    version: int
+    created_at: datetime
+    updated_at: datetime
+    deleted_at: datetime | None
+
+
+def _memo_excerpt(content: str) -> str:
+    collapsed = " ".join(content.split())
+    return collapsed if len(collapsed) <= 120 else collapsed[:119] + "…"
+
+
+@router.get("/memos")
+async def list_memos(
+    scope: str = Query("active", pattern="^(active|trash)$"),
+    q: str = "",
+    page: int = Query(1, ge=1),
+    page_size: int = Query(50, ge=1, le=100),
+    user: User = Depends(current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    filters = [Memo.user_id == user.id]
+    filters.append(Memo.deleted_at.is_(None) if scope == "active" else Memo.deleted_at.is_not(None))
+    query = q.strip()
+    if query:
+        pattern = f"%{query}%"
+        filters.append((Memo.title.ilike(pattern)) | (Memo.content.ilike(pattern)))
+    total = await db.scalar(select(func.count()).select_from(Memo).where(*filters))
+    rows = (await db.scalars(
+        select(Memo).where(*filters).order_by(Memo.updated_at.desc(), Memo.id.desc())
+        .offset((page - 1) * page_size).limit(page_size)
+    )).all()
+    items = [MemoListItem(
+        id=row.id, title=row.title, excerpt=_memo_excerpt(row.content), version=row.version,
+        created_at=row.created_at, updated_at=row.updated_at, deleted_at=row.deleted_at,
+    ) for row in rows]
+    return {"items": items, "total": total or 0, "page": page, "page_size": page_size}
+
+
+@router.post("/memos", response_model=MemoOut, status_code=201)
+async def create_memo(payload: MemoCreate, user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    row = Memo(user_id=user.id, title=payload.title, content=payload.content)
+    db.add(row)
+    await db.flush()
+    audit(db, user.id, "create", "memo", row.id, fields=["title"])
+    await db.commit()
+    await db.refresh(row)
+    return row
+
+
+@router.patch("/memos/{memo_id}", response_model=MemoOut)
+async def update_memo(
+    memo_id: UUID, payload: MemoUpdate, user: User = Depends(current_user), db: AsyncSession = Depends(get_db)
+):
+    existing = await db.scalar(select(Memo).where(Memo.id == memo_id, Memo.user_id == user.id))
+    if not existing:
+        raise HTTPException(404, "备忘录不存在")
+    if existing.deleted_at is not None:
+        raise HTTPException(409, "已删除的备忘录不能编辑")
+    values = payload.model_dump(exclude={"version"}, exclude_unset=True)
+    now = utcnow()
+    result = await db.execute(
+        update(Memo).where(
+            Memo.id == memo_id, Memo.user_id == user.id, Memo.deleted_at.is_(None), Memo.version == payload.version
+        ).values(**values, version=Memo.version + 1, updated_at=now)
+    )
+    if result.rowcount != 1:
+        raise HTTPException(409, "备忘录版本冲突")
+    audit(db, user.id, "update", "memo", memo_id, fields=sorted(values))
+    await db.commit()
+    return await db.scalar(select(Memo).where(Memo.id == memo_id, Memo.user_id == user.id))
+
+
+@router.post("/memos/{memo_id}/restore", response_model=MemoOut)
+async def restore_memo(memo_id: UUID, user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    row = await db.scalar(select(Memo).where(Memo.id == memo_id, Memo.user_id == user.id))
+    if not row:
+        raise HTTPException(404, "备忘录不存在")
+    if row.deleted_at is not None:
+        row.deleted_at = None
+        row.updated_at = utcnow()
+        audit(db, user.id, "restore", "memo", row.id)
+        await db.commit()
+        await db.refresh(row)
+    return row
+
+
+@router.delete("/memos/{memo_id}/purge", status_code=204)
+async def purge_memo(memo_id: UUID, user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    row = await db.scalar(select(Memo).where(Memo.id == memo_id, Memo.user_id == user.id))
+    if not row:
+        raise HTTPException(404, "备忘录不存在")
+    if row.deleted_at is None:
+        raise HTTPException(409, "只能永久删除回收站中的备忘录")
+    audit(db, user.id, "purge", "memo", row.id)
+    await db.delete(row)
+    await db.commit()
+    return Response(status_code=204)
+
+
+@router.delete("/memos/{memo_id}", status_code=204)
+async def delete_memo(memo_id: UUID, user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    row = await db.scalar(select(Memo).where(Memo.id == memo_id, Memo.user_id == user.id))
+    if not row:
+        raise HTTPException(404, "备忘录不存在")
+    if row.deleted_at is None:
+        now = utcnow()
+        row.deleted_at = now
+        row.updated_at = now
+        audit(db, user.id, "delete", "memo", row.id)
+        await db.commit()
+    return Response(status_code=204)
+
+
+@router.get("/memos/{memo_id}", response_model=MemoOut)
+async def get_memo(memo_id: UUID, user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    row = await db.scalar(select(Memo).where(Memo.id == memo_id, Memo.user_id == user.id))
+    if not row:
+        raise HTTPException(404, "备忘录不存在")
+    return row
+
+
 class RecurrenceCreate(BaseModel):
     task_id: UUID
     rrule: str | None = Field(default=None, min_length=5, max_length=1000)
@@ -1101,7 +1268,7 @@ def _serialize_export_value(value):
     return value
 
 
-def _export_payload(folders, lists, tasks, recurrences, habits, countdowns):
+def _export_payload(folders, lists, tasks, recurrences, habits, countdowns, memos):
     def serialize(row, fields):
         return {field: _serialize_export_value(getattr(row, field)) for field in fields}
 
@@ -1114,6 +1281,7 @@ def _export_payload(folders, lists, tasks, recurrences, habits, countdowns):
         "recurrences": [serialize(x, ["id", "task_id", "rrule", "starts_at", "ends_at", "trigger_mode", "after_completion_days", "last_completed_at"]) for x in recurrences],
         "habits": [serialize(x, ["id", "name", "kind", "target", "max_value", "schedule_type", "weekdays", "month_days", "interval_days", "start_date", "archived_at", "position"]) for x in habits],
         "countdowns": [serialize(x, ["id", "title", "event_date", "calendar_mode", "lunar_month", "lunar_day", "ignore_year", "kind", "repeat_rule", "icon", "pinned", "archived_at", "created_at", "updated_at"]) for x in countdowns],
+        "memos": [serialize(x, ["id", "title", "content", "version", "created_at", "updated_at", "deleted_at"]) for x in memos],
     }
 
 
@@ -1124,7 +1292,8 @@ async def _load_export_rows(user, db):
     habits = list((await db.scalars(select(Habit).where(Habit.user_id == user.id))).all())
     countdowns = list((await db.scalars(select(Countdown).where(Countdown.user_id == user.id))).all())
     recurrences = list((await db.scalars(select(RecurrenceTemplate).where(RecurrenceTemplate.user_id == user.id))).all())
-    return folders, lists, tasks, recurrences, habits, countdowns
+    memos = list((await db.scalars(select(Memo).where(Memo.user_id == user.id))).all())
+    return folders, lists, tasks, recurrences, habits, countdowns, memos
 
 
 @router.get("/export")
@@ -1138,7 +1307,7 @@ async def export_csv(user: User = Depends(current_user), db: AsyncSession = Depe
     output = io.StringIO()
     writer = csv.writer(output, lineterminator="\n")
     writer.writerow(["entity", "data"])
-    for entity in ("folders", "lists", "tasks", "recurrences", "habits", "countdowns"):
+    for entity in ("folders", "lists", "tasks", "recurrences", "habits", "countdowns", "memos"):
         for row in payload[entity]:
             writer.writerow([entity, json.dumps(row, ensure_ascii=False, separators=(",", ":"))])
     content = "\ufeff" + output.getvalue()
@@ -1165,6 +1334,7 @@ async def restore_csv(
         "recurrences": [],
         "habits": [],
         "countdowns": [],
+        "memos": [],
     }
     try:
         for row in csv.DictReader(io.StringIO(text)):
@@ -1246,6 +1416,7 @@ async def restore_json(payload: dict, mode: str = Query("merge", pattern="^(merg
         raise HTTPException(422, "不支持的备份版本")
     parsed_countdowns = _validate_countdown_backups(payload)
     if mode == "replace":
+        await db.execute(delete(Memo).where(Memo.user_id == user.id))
         await db.execute(delete(Countdown).where(Countdown.user_id == user.id))
         await db.execute(delete(Task).where(Task.user_id == user.id))
         await db.execute(delete(Habit).where(Habit.user_id == user.id))
@@ -1372,6 +1543,35 @@ async def restore_json(payload: dict, mode: str = Query("merge", pattern="^(merg
         existing_countdown_ids.add(row_id)
         occupied_countdown_ids[row_id] = user.id
         restored += 1
+    existing_memo_ids = set((await db.scalars(select(Memo.id).where(Memo.user_id == user.id))).all())
+    for raw in payload.get("memos", []):
+        try:
+            source_id = UUID(raw["id"])
+            title = raw["title"].strip()
+            content = raw.get("content", "")
+            version = raw.get("version", 1)
+            if not title or len(title) > 200 or not isinstance(content, str):
+                raise ValueError
+            if not isinstance(version, int) or isinstance(version, bool) or version < 1:
+                raise ValueError
+            created_at = datetime.fromisoformat(raw["created_at"])
+            updated_at = datetime.fromisoformat(raw["updated_at"])
+            deleted_at = datetime.fromisoformat(raw["deleted_at"]) if raw.get("deleted_at") else None
+        except (KeyError, TypeError, ValueError) as exc:
+            raise HTTPException(422, "无效的备忘录备份数据") from exc
+        occupied_user = await db.scalar(select(Memo.user_id).where(Memo.id == source_id))
+        row_id = source_id
+        while occupied_user not in (None, user.id):
+            row_id = uuid5(user.id, str(row_id))
+            occupied_user = await db.scalar(select(Memo.user_id).where(Memo.id == row_id))
+        if mode == "merge" and row_id in existing_memo_ids:
+            continue
+        db.add(Memo(
+            id=row_id, user_id=user.id, title=title, content=content, version=version,
+            created_at=created_at, updated_at=updated_at, deleted_at=deleted_at,
+        ))
+        existing_memo_ids.add(row_id)
+        restored += 1
     audit(db, user.id, "restore", "backup", count=restored, mode=mode)
     await db.commit()
     return {"restored": restored, "mode": mode}
diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index 8100b30..0db6287 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -3,7 +3,7 @@ import { computed, nextTick, onMounted, onUnmounted, ref, watch } from 'vue'
 import {
   ArchiveRestore, Bold, CalendarDays, CalendarHeart, Check, ChevronDown, ChevronRight, Code, Folder,
   Ellipsis, GripVertical, Heading2, Inbox, Italic, Link, List, ListChecks, ListOrdered, ListTodo, Menu, Pencil, Plus, Quote, Search,
-  Settings, Trash2, X, Repeat2, RefreshCw,
+  Settings, Trash2, X, Repeat2, RefreshCw, StickyNote,
 } from 'lucide-vue-next'
 import { applyMarkdownFormat, buildTaskRecurrencePayload, defaultTaskDueAt, filterTasks, fromDateTimeLocal, groupTaskTree, isSameTaskSortTier, moveItemWithinScope, parseTaskRecurrence, parseTaskRrule, renderMarkdown, toDateTimeLocal, type MarkdownFormat, type TaskRepeatConfig, type TaskRepeatOption } from './lib/task-utils'
 import { beginLatestRequest, createMutationReconciler, formatApiErrorDetail, isLatestRequest, isTaskView, loadCountdownCache, nextTotalAfterLocalTaskAdd, nextTotalAfterLocalTaskRemoval, normalizeRequiredName, performTrashMutation, readStoredBoolean, readStoredNavigation, runLatestRequest, shouldToggleRowSwipe, startPrimaryWithBackground, writeStoredBoolean, writeStoredNavigation } from './lib/mvp-utils'
@@ -15,6 +15,7 @@ import { nextDialogFocusIndex } from './lib/list-purge'
 import { positionArchivedMenu, resolveArchivedMenuFocusTarget } from './lib/archived-list-menu'
 import MvpPanel from './MvpPanel.vue'
 import CountdownPanel from './CountdownPanel.vue'
+import MemoPanel from './MemoPanel.vue'
 import FloatingAddButton from './components/FloatingAddButton.vue'
 import CompletedFilterPill from './components/CompletedFilterPill.vue'
 import CalendarPicker from './components/CalendarPicker.vue'
@@ -26,7 +27,7 @@ type TaskList = { id: string; folder_id: string | null; name: string; is_inbox:
 type Task = { id: string; list_id: string; parent_id: string | null; title: string; description: string; priority: number; completed: boolean; version: number; due_at: string | null; due_has_time: boolean; subtasks?: Task[] }
 type RepeatOption = TaskRepeatOption
 type Recurrence = { id: string; task_id: string; rrule: string | null; trigger_mode: 'scheduled' | 'after_completion'; after_completion_days: number | null }
-type View = 'tasks' | 'today' | 'upcoming' | 'trash' | 'habits' | 'countdowns' | 'settings'
+type View = 'tasks' | 'today' | 'upcoming' | 'trash' | 'habits' | 'countdowns' | 'memos' | 'settings'
 
 const initialized = ref<boolean | null>(null)
 const authReady = ref(false)
@@ -152,6 +153,8 @@ let recurrenceLoadToken = 0
 let todaySummaryLoadToken = 0
 const habitComposer = ref<InstanceType<typeof MvpPanel> | null>(null)
 const countdownComposer = ref<InstanceType<typeof CountdownPanel> | null>(null)
+const memoPanel = ref<InstanceType<typeof MemoPanel> | null>(null)
+const memoTrash = ref(false)
 const composeOrigin = ref({ x: window.innerWidth - 43, y: window.innerHeight - 104 })
 let suppressTaskClickId = ''
 
@@ -199,6 +202,7 @@ function activateFloatingAdd(origin: { x: number; y: number }) {
   composeOrigin.value = origin
   if (activeView.value === 'habits') habitComposer.value?.openHabitComposer(origin)
   else if (activeView.value === 'countdowns') countdownComposer.value?.openCountdownComposer(origin)
+  else if (activeView.value === 'memos') void memoPanel.value?.createMemo()
   else if (['tasks', 'today', 'upcoming'].includes(activeView.value)) openTaskCompose()
 }
 async function saveRepeat(task: Task, value: RepeatOption, config: TaskRepeatConfig, afterCompletionDays: string, recurrence: Recurrence | null) {
@@ -316,6 +320,7 @@ const activeName = computed(() => {
   if (activeView.value === 'upcoming') return '最近 7 天'
   if (activeView.value === 'habits') return '习惯'
   if (activeView.value === 'countdowns') return '倒数日'
+  if (activeView.value === 'memos') return '备忘录'
   if (activeView.value === 'settings') return '设置与数据'
   return lists.value.find((item) => item.id === activeList.value)?.name || '收集箱'
 })
@@ -335,7 +340,7 @@ const visibleTasks = computed(() => {
   const now = new Date()
   const end = new Date(now); end.setDate(end.getDate() + 7)
   let result = sourceTasks.value
-  if (['habits','settings','countdowns'].includes(activeView.value)) return []
+  if (['habits','settings','countdowns','memos'].includes(activeView.value)) return []
   if (activeView.value === 'today') result = result.filter((task) => task.due_at && new Date(task.due_at).toDateString() === now.toDateString())
   if (activeView.value === 'upcoming') result = result.filter((task) => task.due_at && new Date(task.due_at) >= now && new Date(task.due_at) <= end)
   return query.value.trim() ? filterTasks(result, query.value) : result
@@ -374,7 +379,9 @@ async function api(path: string, options: RequestInit = {}) {
   if (!response.ok) {
     let message = '请求失败'
     try { const body = await response.json(); message = formatApiErrorDetail(body.detail) } catch { /* noop */ }
-    throw new Error(message)
+    const requestError = new Error(message) as Error & { status: number }
+    requestError.status = response.status
+    throw requestError
   }
   return response.status === 204 ? null : response.json()
 }
@@ -596,6 +603,7 @@ async function loadTrash() {
   })
 }
 async function switchView(view: View, listId?: string) {
+  if (activeView.value === 'memos' && view !== 'memos' && memoPanel.value?.dirty && !window.confirm('有未保存的更改，确定离开吗？')) return
   taskMutationNavigation.value += 1
   activeView.value = view
   if (!query.value) mobileSearchOpen.value = false
@@ -1336,6 +1344,7 @@ onUnmounted(() => {
         <button :class="{ active: activeView==='upcoming' }" @click="switchView('upcoming')"><CalendarDays />最近 7 天</button>
         <button :class="{ active: activeView==='habits' }" @click="switchView('habits')"><Repeat2 />习惯</button>
         <button :class="{ active: activeView==='countdowns' }" @click="switchView('countdowns')"><CalendarHeart />倒数日</button>
+        <button :class="{ active: activeView==='memos' }" @click="switchView('memos')"><StickyNote />备忘录</button>
       </nav>
       <div class="section-title list-root-drop" :class="{'list-drop-target':listDrag&&listDropFolderId===null&&!listReorderTarget}" @pointermove="listDrag&&resolveListDrop($event)"><span>我的清单</span><span class="sidebar-create-wrap"><button class="mini-icon list-create-trigger" aria-label="新建清单或文件夹" :aria-expanded="sidebarCreateOpen" @click="toggleSidebarCreate"><Plus /></button><span v-if="sidebarCreateOpen" class="sidebar-popover sidebar-create-menu"><button @click="runSidebarCreate('list')"><ListTodo/>新建清单</button><button @click="runSidebarCreate('folder')"><Folder/>新建文件夹</button></span></span></div>
       <div class="folders">
@@ -1413,6 +1422,7 @@ onUnmounted(() => {
       <template v-if="['habits','settings'].includes(activeView)">
         <MvpPanel ref="habitComposer" :key="activeView" :view="activeView as 'habits'|'settings'" :show-completed="showCompleted" @changed="refreshAll" @notice="toast" />
       </template>
+      <MemoPanel v-else-if="activeView==='memos'" ref="memoPanel" :request="api" @scope="memoTrash=$event==='trash'" @notice="toast" />
       <CountdownPanel ref="countdownComposer" v-else-if="activeView==='countdowns'" @notice="toast" />
       <template v-else>
         <section v-if="activeView==='today'" class="today-board" aria-label="今日进度">
@@ -1468,7 +1478,7 @@ onUnmounted(() => {
         <section v-if="selectedTaskRepeat==='custom'" class="repeat-custom-fields"><div><span>每隔</span><input v-model.number="selectedRepeatConfig.interval" type="number" min="1"><select v-model="selectedRepeatConfig.frequency"><option value="daily">天</option><option value="weekly">周</option><option value="monthly">月</option><option value="yearly">年</option></select></div><label v-if="selectedRepeatConfig.frequency==='weekly'">重复日期<span class="weekday-picker"><label v-for="day in weekdayOptions" :key="day.value"><input v-model="selectedRepeatConfig.weekdays" type="checkbox" :value="day.value">{{day.label}}</label></span></label><label v-if="selectedRepeatConfig.frequency==='monthly'">每月日期<input v-model="selectedRepeatConfig.monthDays" placeholder="例如 1,15,31" @change="selectedRepeatConfig.monthDays=String(($event.target as HTMLInputElement).value).split(',').map(Number).filter(Boolean)"></label><label>结束方式<select v-model="selectedRepeatConfig.endMode"><option value="never">永不结束</option><option value="date">指定日期</option><option value="count">重复次数</option></select></label><label v-if="selectedRepeatConfig.endMode==='date'">结束日期<input v-model="selectedRepeatConfig.until" type="date"></label><label v-if="selectedRepeatConfig.endMode==='count'">重复次数<input v-model.number="selectedRepeatConfig.count" type="number" min="1"></label></section>
         <small v-if="selectedRepeatError" role="alert" class="field-error">{{selectedRepeatError}}</small>
         <div class="field markdown">
-          <div class="field-label"><span>备注</span><span class="markdown-mode-switch"><button type="button" :aria-pressed="!markdownPreview" :class="{active:!markdownPreview}" @click="markdownPreview=false">编辑</button><button type="button" :aria-pressed="markdownPreview" :class="{active:markdownPreview}" @click="markdownPreview=true">预览</button></span></div>
+          <div class="field-label"><span>任务备注</span><span class="markdown-mode-switch"><button type="button" :aria-pressed="!markdownPreview" :class="{active:!markdownPreview}" @click="markdownPreview=false">编辑</button><button type="button" :aria-pressed="markdownPreview" :class="{active:markdownPreview}" @click="markdownPreview=true">预览</button></span></div>
           <div v-if="!markdownPreview" class="markdown-editor-shell">
             <div class="markdown-toolbar" role="toolbar" aria-label="Markdown 格式">
               <button type="button" aria-label="标题" title="标题" @click="formatTaskNote('heading')"><Heading2/></button>
@@ -1496,7 +1506,7 @@ onUnmounted(() => {
 
     <div v-if="mobileMore" class="more-mask app-sheet-mask" @click.self="mobileMore=false;switchView('settings')"><section id="mobile-more-menu" class="more-sheet app-sheet app-sheet--actions" role="dialog" aria-modal="true" aria-label="更多导航" @click.stop><div class="more-sheet-head app-sheet__header"><b>更多</b><button class="icon" aria-label="关闭更多菜单" @click="mobileMore=false"><X/></button></div><div class="app-sheet__body"><button @click="switchView('settings')"><Settings/>设置与数据</button></div></section></div>
     <nav class="bottom" aria-label="主要导航"><button :class="{active:activeView==='today'}" :aria-current="activeView==='today' ? 'page' : undefined" @click="switchView('today')"><ListTodo/><span>今天</span></button><button :class="{active:activeView==='habits'}" :aria-current="activeView==='habits' ? 'page' : undefined" @click="switchView('habits')"><Repeat2/><span>习惯</span></button><button :class="{active:activeView==='countdowns'}" :aria-current="activeView==='countdowns' ? 'page' : undefined" @click="switchView('countdowns')"><CalendarHeart/><span>倒数日</span></button><button :class="{active:activeView==='settings'}" :aria-current="activeView==='settings' ? 'page' : undefined" @click="switchView('settings')"><Settings/><span>设置</span></button></nav>
-    <FloatingAddButton v-if="['tasks','today','upcoming','habits','countdowns'].includes(activeView)" :label="activeView==='habits' ? '添加习惯' : activeView==='countdowns' ? '添加倒数日' : '添加任务'" @activate="activateFloatingAdd" />
+    <FloatingAddButton v-if="['tasks','today','upcoming','habits','countdowns','memos'].includes(activeView)" :show="activeView!=='memos' || !memoTrash" :label="activeView==='habits' ? '添加习惯' : activeView==='countdowns' ? '添加倒数日' : activeView==='memos' ? '添加备忘录' : '添加任务'" @activate="activateFloatingAdd" />
     <Transition name="task-compose">
       <div v-if="taskComposeOpen" class="task-compose-mask app-sheet-mask" @click.self="closeTaskCompose">
         <form class="task-compose-sheet app-sheet app-sheet--create" :style="taskComposeStyle" role="dialog" aria-modal="true" aria-labelledby="task-compose-title" @submit.prevent="submitTaskCompose">
diff --git a/frontend/src/MemoIntegration.test.ts b/frontend/src/MemoIntegration.test.ts
new file mode 100644
index 0000000..92b4e45
--- /dev/null
+++ b/frontend/src/MemoIntegration.test.ts
@@ -0,0 +1,45 @@
+import { readFileSync } from 'node:fs'
+import { describe, expect, it } from 'vitest'
+
+const app = readFileSync('src/App.vue', 'utf8')
+const css = readFileSync('src/memo.css', 'utf8')
+const panel = readFileSync('src/MemoPanel.vue', 'utf8')
+const editor = readFileSync('src/components/MemoEditor.vue', 'utf8')
+
+describe('memo shell integration', () => {
+  it('places Memos immediately after Countdowns in desktop navigation and keeps mobile tabs unchanged', () => {
+    const nav = app.slice(app.indexOf('<nav class="primary-nav">'), app.indexOf('</nav>', app.indexOf('<nav class="primary-nav">')))
+    expect(nav.indexOf("switchView('memos')")).toBeGreaterThan(nav.indexOf("switchView('countdowns')"))
+    expect(nav.match(/switchView\('memos'\)/g)).toHaveLength(1)
+    const bottom = app.slice(app.indexOf('<nav class="bottom"'), app.indexOf('</nav>', app.indexOf('<nav class="bottom"')))
+    expect(bottom).not.toContain("switchView('memos')")
+    expect(bottom.match(/aria-current=/g)).toHaveLength(4)
+  })
+
+  it('routes the shared cat FAB to memo creation and hides it in memo trash', () => {
+    expect(app).toContain("activeView.value === 'memos'")
+    expect(app).toContain('memoPanel.value?.createMemo()')
+    expect(app).toContain(':show="activeView!==\'memos\' || !memoTrash"')
+    expect(panel).toContain("scope.value === 'trash'")
+  })
+
+  it('keeps memo UI componentized and task detail copy explicit', () => {
+    expect(app).toContain("import MemoPanel from './MemoPanel.vue'")
+    expect(panel).toContain("import MemoRow")
+    expect(panel).toContain("import MemoEditor")
+    expect(app).toContain('<span>任务详情</span>')
+    expect(app).toContain('<div class="field-label"><span>任务备注</span>')
+  })
+
+  it('uses a 350px desktop detail, near-full mobile sheet, continuous rows and reduced motion', () => {
+    expect(css).toContain('.memo-editor{width:350px')
+    expect(css).toContain('.memo-list{display:grid;gap:0')
+    expect(css).toContain('.memo-row+.memo-row{border-top:1px solid var(--border-cream)}')
+    expect(css).toContain('@media(max-width:930px){.memo-panel{')
+    expect(css).toContain('.memo-editor{position:fixed;z-index:42;left:0;right:0;top:auto')
+    expect(css).toContain('height:min(92dvh,820px)')
+    expect(css).toContain('@media(prefers-reduced-motion:reduce){.memo-editor')
+    expect(editor).toContain("window.addEventListener('beforeunload'")
+    expect(editor).toContain("event.key !== 'Tab'")
+  })
+})
diff --git a/frontend/src/MemoPanel.test.ts b/frontend/src/MemoPanel.test.ts
new file mode 100644
index 0000000..650cc7a
--- /dev/null
+++ b/frontend/src/MemoPanel.test.ts
@@ -0,0 +1,73 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { createApp, h, nextTick } from 'vue'
+import MemoPanel from './MemoPanel.vue'
+
+const cleanups: Array<() => void> = []
+const item = { id: 'm1', title: '第一条', excerpt: '摘要', version: 1, created_at: '2026-09-12T01:00:00Z', updated_at: '2026-09-12T02:00:00Z', deleted_at: null }
+
+type RequestMock = ReturnType<typeof vi.fn<(path: string, options?: RequestInit) => Promise<unknown>>>
+
+async function mount(request: RequestMock) {
+  const host = document.createElement('div'); document.body.append(host)
+  let panel: InstanceType<typeof MemoPanel> | null = null
+  const app = createApp(() => h(MemoPanel, { ref: (value: unknown) => { panel = value as InstanceType<typeof MemoPanel> }, request }))
+  app.mount(host)
+  cleanups.push(() => { app.unmount(); host.remove() })
+  await Promise.resolve(); await Promise.resolve(); await nextTick()
+  return { host, vm: panel! }
+}
+afterEach(() => { vi.useRealTimers(); cleanups.splice(0).forEach((cleanup) => cleanup()) })
+
+describe('MemoPanel', () => {
+  it('loads active memos in server order and appends the next 50', async () => {
+    const request = vi.fn(async (path: string) => path.includes('page=2')
+      ? { items: [{ ...item, id: 'm2', title: '第二页' }], total: 51 }
+      : { items: [item], total: 51 })
+    const { host } = await mount(request)
+    expect(request.mock.calls[0][0]).toContain('/memos?scope=active')
+    expect(request.mock.calls[0][0]).toContain('page_size=50')
+    expect(host.querySelectorAll('.memo-row')).toHaveLength(1)
+    host.querySelector<HTMLButtonElement>('.memo-load-more')!.click(); await new Promise((resolve) => setTimeout(resolve, 0)); await nextTick()
+    expect([...host.querySelectorAll('.memo-row strong')].map((node) => node.textContent)).toEqual(['第一条', '第二页'])
+  })
+
+  it('searches title and body through the server and has a search empty state', async () => {
+    vi.useFakeTimers()
+    const request = vi.fn(async (_path: string, _options?: RequestInit): Promise<unknown> => ({ items: [], total: 0 }))
+    const { host } = await mount(request)
+    const input = host.querySelector<HTMLInputElement>('[aria-label="搜索备忘录"]')!
+    input.value = '咖啡'; input.dispatchEvent(new Event('input'))
+    await vi.advanceTimersByTimeAsync(260); await nextTick()
+    expect(request.mock.calls.at(-1)?.[0]).toContain('q=%E5%92%96%E5%95%A1')
+    expect(host.textContent).toContain('没有匹配的备忘录')
+    vi.useRealTimers()
+  })
+
+  it('only makes the memo list inert while the detail is a mobile sheet', async () => {
+    const originalWidth = window.innerWidth
+    const request = vi.fn(async (path: string) => path.startsWith('/memos/m1') ? { ...item, content: '正文' } : { items: [item], total: 1 })
+    Object.defineProperty(window, 'innerWidth', { configurable: true, value: 1200 })
+    const desktop = await mount(request)
+    desktop.host.querySelector<HTMLButtonElement>('.memo-row')!.click(); await Promise.resolve(); await nextTick()
+    expect(desktop.host.querySelector('.memo-panel__main')?.hasAttribute('inert')).toBe(false)
+    expect(desktop.host.querySelector('.memo-editor')?.hasAttribute('aria-modal')).toBe(false)
+    Object.defineProperty(window, 'innerWidth', { configurable: true, value: 390 })
+    window.dispatchEvent(new Event('resize')); await nextTick()
+    expect(desktop.host.querySelector('.memo-panel__main')?.hasAttribute('inert')).toBe(true)
+    expect(desktop.host.querySelector('.memo-editor')?.getAttribute('aria-modal')).toBe('true')
+    Object.defineProperty(window, 'innerWidth', { configurable: true, value: originalWidth })
+  })
+
+  it('switches between active and trash and creates through the exposed FAB action', async () => {
+    const request = vi.fn(async (path: string, options?: RequestInit) => options?.method === 'POST'
+      ? { ...item, id: 'new', title: '未命名备忘录', content: '', excerpt: '' }
+      : { items: [], total: 0 })
+    const { host, vm } = await mount(request)
+    host.querySelector<HTMLButtonElement>('[data-scope="trash"]')!.click(); await Promise.resolve(); await Promise.resolve(); await nextTick()
+    expect(request.mock.calls.at(-1)?.[0]).toContain('scope=trash')
+    host.querySelector<HTMLButtonElement>('[data-scope="active"]')!.click(); await Promise.resolve(); await Promise.resolve(); await nextTick()
+    await vm.createMemo()
+    expect(request).toHaveBeenCalledWith('/memos', { method: 'POST', body: JSON.stringify({ title: '未命名备忘录', content: '' }) })
+    expect(host.querySelector('.memo-editor')).not.toBeNull()
+  })
+})
diff --git a/frontend/src/MemoPanel.vue b/frontend/src/MemoPanel.vue
new file mode 100644
index 0000000..a7c683b
--- /dev/null
+++ b/frontend/src/MemoPanel.vue
@@ -0,0 +1,90 @@
+<script setup lang="ts">
+import { computed, nextTick, onMounted, onUnmounted, ref, watch } from 'vue'
+import { Archive, FileText, Search } from 'lucide-vue-next'
+import MemoRow, { type MemoListItem } from './components/MemoRow.vue'
+import MemoEditor, { type Memo } from './components/MemoEditor.vue'
+
+type RequestFn = (path: string, options?: RequestInit) => Promise<unknown>
+const props = defineProps<{ request: RequestFn }>()
+const emit = defineEmits<{ notice: [message: string]; scope: [scope: 'active' | 'trash'] }>()
+const scope = ref<'active' | 'trash'>('active')
+const query = ref('')
+const items = ref<MemoListItem[]>([])
+const total = ref(0)
+const page = ref(1)
+const loading = ref(false)
+const refreshing = ref(false)
+const error = ref('')
+const selected = ref<Memo | null>(null)
+const editor = ref<InstanceType<typeof MemoEditor> | null>(null)
+const mobileDetail = ref(window.innerWidth <= 930)
+let timer: number | undefined
+let generation = 0
+const hasMore = computed(() => items.value.length < total.value)
+const emptyCopy = computed(() => query.value.trim() ? '没有匹配的备忘录' : scope.value === 'trash' ? '回收站是空的' : '还没有备忘录')
+
+async function load(reset = true) {
+  const token = ++generation
+  if (reset) { page.value = 1; loading.value = true } else refreshing.value = true
+  error.value = ''
+  try {
+    const params = new URLSearchParams({ scope: scope.value, q: query.value.trim(), page: String(page.value), page_size: '50' })
+    const data = await props.request(`/memos?${params}`) as { items: MemoListItem[]; total: number }
+    if (token !== generation) return
+    items.value = reset ? data.items : [...items.value, ...data.items]
+    total.value = data.total
+  } catch (reason) { if (token === generation) error.value = reason instanceof Error ? reason.message : '加载失败' }
+  finally { if (token === generation) { loading.value = false; refreshing.value = false } }
+}
+async function loadMore() { if (!hasMore.value || refreshing.value) return; page.value += 1; await load(false) }
+async function setScope(next: 'active' | 'trash') {
+  if (next === scope.value) return
+  if (editor.value?.dirty && !window.confirm('有未保存的更改，确定切换吗？')) return
+  selected.value = null; scope.value = next; emit('scope', next); await load()
+}
+async function selectMemo(id: string) {
+  if (editor.value?.dirty && !window.confirm('有未保存的更改，确定切换吗？')) return
+  try { selected.value = await props.request(`/memos/${id}`) as Memo } catch (reason) { error.value = reason instanceof Error ? reason.message : '读取失败' }
+}
+async function createMemo() {
+  if (scope.value === 'trash') return
+  if (editor.value?.dirty && !window.confirm('有未保存的更改，确定新建吗？')) return
+  try {
+    const created = await props.request('/memos', { method: 'POST', body: JSON.stringify({ title: '未命名备忘录', content: '' }) }) as Memo
+    items.value = [{ ...created, excerpt: '' }, ...items.value]; total.value += 1; selected.value = created
+    emit('notice', '备忘录已创建')
+  } catch (reason) { error.value = reason instanceof Error ? reason.message : '创建失败' }
+}
+function updateItem(memo: Memo) {
+  selected.value = memo
+  const index = items.value.findIndex((item) => item.id === memo.id)
+  if (index >= 0) items.value[index] = { ...memo, excerpt: memo.content.replace(/\s+/g, ' ').trim().slice(0, 120) }
+}
+function removeItem(id: string) { items.value = items.value.filter((item) => item.id !== id); total.value = Math.max(0, total.value - 1); selected.value = null }
+function removeRestoredItem(memo: Memo) { removeItem(memo.id) }
+function updateLayout() { mobileDetail.value = window.innerWidth <= 930 }
+watch(query, () => { if (timer) clearTimeout(timer); timer = window.setTimeout(() => void load(), 250) })
+onMounted(() => { window.addEventListener('resize', updateLayout); void load() })
+onUnmounted(() => { window.removeEventListener('resize', updateLayout); if (timer) clearTimeout(timer) })
+defineExpose({ createMemo, requestClose: () => editor.value?.requestClose(), dirty: computed(() => Boolean(editor.value?.dirty)) })
+</script>
+
+<template>
+  <section class="memo-panel" :class="{'memo-panel--detail':selected}">
+    <div class="memo-panel__main" :inert="selected && mobileDetail ? true : undefined">
+      <div class="memo-toolbar">
+        <div class="memo-scope" role="tablist" aria-label="备忘录范围"><button role="tab" data-scope="active" :aria-selected="scope==='active'" @click="setScope('active')">活动</button><button role="tab" data-scope="trash" :aria-selected="scope==='trash'" @click="setScope('trash')"><Archive/>回收站</button></div>
+        <label class="memo-search"><Search/><input v-model="query" aria-label="搜索备忘录" placeholder="搜索标题或正文…"></label>
+      </div>
+      <p v-if="error" class="memo-error" role="alert">{{error}} <button class="link" @click="load()">重试</button></p>
+      <div v-if="loading && !items.length" class="memo-state"><span class="loader"/>正在载入备忘录…</div>
+      <div v-else-if="!items.length" class="memo-state"><FileText/><b>{{emptyCopy}}</b><span>{{query ? '换个关键词试试' : scope==='trash' ? '删除的备忘录会显示在这里' : '点击右下角团子猫新建一条'}}</span></div>
+      <div v-else class="memo-list" :class="{refreshing}" aria-live="polite">
+        <MemoRow v-for="memo in items" :key="memo.id" :memo="memo" :active="selected?.id===memo.id" @select="selectMemo"/>
+      </div>
+      <button v-if="hasMore" class="secondary memo-load-more" :disabled="refreshing" @click="loadMore">{{refreshing?'正在加载…':'加载更多'}}</button>
+    </div>
+    <div v-if="selected" class="memo-editor-scrim" @click="editor?.requestClose()"/>
+    <MemoEditor v-if="selected" ref="editor" :memo="selected" :request="request" :mobile="mobileDetail" @saved="updateItem" @close="selected=null" @deleted="removeItem" @restored="removeRestoredItem" @purged="removeItem" @notice="emit('notice',$event)"/>
+  </section>
+</template>
diff --git a/frontend/src/components/FloatingAddButton.vue b/frontend/src/components/FloatingAddButton.vue
index f59b143..edd3aac 100644
--- a/frontend/src/components/FloatingAddButton.vue
+++ b/frontend/src/components/FloatingAddButton.vue
@@ -2,7 +2,7 @@
 import { computed, onMounted, onUnmounted, ref } from 'vue'
 import { clampFabPosition, isFabDrag, snapFabPosition } from '../lib/mvp-utils'
 
-const props = withDefaults(defineProps<{ label?: string }>(), { label: '添加' })
+const props = withDefaults(defineProps<{ label?: string; show?: boolean }>(), { label: '添加', show: true })
 const emit = defineEmits<{ activate: [origin: { x: number; y: number }] }>()
 const dragging = ref(false)
 const snapping = ref(false)
@@ -115,7 +115,7 @@ onUnmounted(() => {
 </script>
 
 <template>
-  <button class="unified-fab" :class="{ dragging, snapping, 'edge-left': edge === 'left', 'edge-right': edge === 'right' }" :style="buttonStyle" :aria-label="props.label" @pointerdown="startDrag" @pointermove="moveDrag" @pointerup="finishDrag" @pointercancel="finishDrag" @click="activate">
+  <button v-if="props.show" class="unified-fab" :class="{ dragging, snapping, 'edge-left': edge === 'left', 'edge-right': edge === 'right' }" :style="buttonStyle" :aria-label="props.label" @pointerdown="startDrag" @pointermove="moveDrag" @pointerup="finishDrag" @pointercancel="finishDrag" @click="activate">
     <svg class="fab-cat" viewBox="0 0 56 56" aria-hidden="true">
       <g class="fab-cat__tail"><path d="M40.5 36.8 C46.2 38.4 47 43.2 43 46"/></g>
       <g class="fab-cat__character">
diff --git a/frontend/src/components/MemoEditor.test.ts b/frontend/src/components/MemoEditor.test.ts
new file mode 100644
index 0000000..d79f7b5
--- /dev/null
+++ b/frontend/src/components/MemoEditor.test.ts
@@ -0,0 +1,93 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { createApp, h, nextTick } from 'vue'
+import MemoEditor, { type Memo } from './MemoEditor.vue'
+
+const cleanups: Array<() => void> = []
+const memo: Memo = { id: 'm1', title: '旧标题', content: '正文', version: 3, created_at: '2026-09-12T01:00:00Z', updated_at: '2026-09-12T02:00:00Z', deleted_at: null }
+
+async function mount(overrides: Record<string, unknown> = {}) {
+  const host = document.createElement('div'); document.body.append(host)
+  const events: Record<string, unknown[]> = { saved: [], close: [] }
+  const defaultRequest = vi.fn(async (_path: string, _options?: RequestInit): Promise<unknown> => ({ ...memo, title: '新标题', version: 4 }))
+  const request = (overrides.request ?? defaultRequest) as (path: string, options?: RequestInit) => Promise<unknown>
+  const app = createApp(() => h(MemoEditor, { memo, request, onSaved: (v: unknown) => events.saved.push(v), onClose: () => events.close.push(true), ...overrides }))
+  app.mount(host); cleanups.push(() => { app.unmount(); host.remove() }); await nextTick()
+  return { host, request: request as ReturnType<typeof vi.fn>, events }
+}
+afterEach(() => { vi.restoreAllMocks(); cleanups.splice(0).forEach((cleanup) => cleanup()) })
+
+describe('MemoEditor', () => {
+  it('requires a 1-200 character title and saves explicitly with its version', async () => {
+    const { host, request, events } = await mount()
+    const title = host.querySelector<HTMLInputElement>('[aria-label="备忘录标题"]')!
+    title.value = '  新标题  '; title.dispatchEvent(new Event('input')); await nextTick()
+    host.querySelector<HTMLButtonElement>('.memo-save')!.click(); await nextTick(); await nextTick()
+    expect(request).toHaveBeenCalledWith('/memos/m1', expect.objectContaining({ method: 'PATCH', body: JSON.stringify({ title: '新标题', content: '正文', version: 3 }) }))
+    expect(events.saved).toHaveLength(1)
+  })
+
+  it('supports Cmd/Ctrl+S and prevents browser save', async () => {
+    const { host, request } = await mount()
+    const title = host.querySelector<HTMLInputElement>('[aria-label="备忘录标题"]')!
+    title.value = '新标题'; title.dispatchEvent(new Event('input'))
+    const event = new KeyboardEvent('keydown', { key: 's', metaKey: true, bubbles: true, cancelable: true })
+    host.querySelector('.memo-editor')!.dispatchEvent(event); await nextTick(); await nextTick()
+    expect(event.defaultPrevented).toBe(true)
+    expect(request).toHaveBeenCalledOnce()
+  })
+
+  it('keeps the draft and offers reload after a 409 conflict', async () => {
+    const request = vi.fn().mockRejectedValue(Object.assign(new Error('备忘录版本冲突'), { status: 409 }))
+    const { host } = await mount({ request })
+    const title = host.querySelector<HTMLInputElement>('[aria-label="备忘录标题"]')!
+    title.value = '我的草稿'; title.dispatchEvent(new Event('input')); await nextTick()
+    host.querySelector<HTMLButtonElement>('.memo-save')!.click(); await new Promise((resolve) => setTimeout(resolve, 0)); await nextTick()
+    expect(title.value).toBe('我的草稿')
+    expect(host.textContent).toContain('版本冲突')
+    expect(host.querySelector('.memo-reload')).not.toBeNull()
+  })
+
+  it('keeps the editor open and reports destructive action failures', async () => {
+    vi.spyOn(window, 'confirm').mockReturnValue(true)
+    const request = vi.fn(async (_path: string, options?: RequestInit): Promise<unknown> => {
+      if (options?.method === 'DELETE') throw new Error('删除失败')
+      return memo
+    })
+    const { host, events } = await mount({ request })
+    host.querySelector<HTMLButtonElement>('.danger-text')!.click()
+    await new Promise((resolve) => setTimeout(resolve, 0)); await nextTick()
+    expect(host.textContent).toContain('删除失败')
+    expect(events.close).toEqual([])
+  })
+
+  it('traps mobile focus, closes on Escape, and restores opener focus', async () => {
+    const opener = document.createElement('button'); document.body.append(opener); opener.focus()
+    const { host, events } = await mount({ mobile: true })
+    const dialog = host.querySelector<HTMLElement>('.memo-editor')!
+    expect(dialog.getAttribute('aria-modal')).toBe('true')
+    const last = [...dialog.querySelectorAll<HTMLElement>('button:not(:disabled),input:not(:disabled),textarea:not(:disabled)')].at(-1)!
+    last.focus()
+    const tab = new KeyboardEvent('keydown', { key: 'Tab', bubbles: true, cancelable: true })
+    dialog.dispatchEvent(tab)
+    expect(tab.defaultPrevented).toBe(true)
+    expect(document.activeElement).toBe(dialog.querySelector('button'))
+    dialog.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true, cancelable: true }))
+    await nextTick()
+    expect(events.close).toEqual([true])
+    expect(document.activeElement).toBe(opener)
+    opener.remove()
+  })
+
+  it('guards dirty close and allows clean close', async () => {
+    const confirm = vi.spyOn(window, 'confirm').mockReturnValue(false)
+    const { host, events } = await mount()
+    const body = host.querySelector<HTMLTextAreaElement>('[aria-label="备忘录正文"]')!
+    body.value = '改过'; body.dispatchEvent(new Event('input')); await nextTick()
+    host.querySelector<HTMLButtonElement>('[aria-label="关闭备忘录"]')!.click()
+    expect(confirm).toHaveBeenCalled()
+    expect(events.close).toEqual([])
+    confirm.mockReturnValue(true)
+    host.querySelector<HTMLButtonElement>('[aria-label="关闭备忘录"]')!.click()
+    expect(events.close).toEqual([true])
+  })
+})
diff --git a/frontend/src/components/MemoEditor.vue b/frontend/src/components/MemoEditor.vue
new file mode 100644
index 0000000..ae7c221
--- /dev/null
+++ b/frontend/src/components/MemoEditor.vue
@@ -0,0 +1,102 @@
+<script setup lang="ts">
+import { computed, nextTick, onMounted, onUnmounted, ref, watch } from 'vue'
+import { ArchiveRestore, Trash2, X } from 'lucide-vue-next'
+
+export type Memo = { id: string; title: string; content: string; version: number; created_at: string; updated_at: string; deleted_at: string | null }
+type RequestFn = (path: string, options?: RequestInit) => Promise<unknown>
+const props = defineProps<{ memo: Memo; request: RequestFn; mobile?: boolean }>()
+const emit = defineEmits<{ saved: [memo: Memo]; close: []; deleted: [id: string]; restored: [memo: Memo]; purged: [id: string]; notice: [message: string] }>()
+const title = ref('')
+const content = ref('')
+const saving = ref(false)
+const error = ref('')
+const conflict = ref(false)
+const titleInput = ref<HTMLInputElement | null>(null)
+const root = ref<HTMLElement | null>(null)
+let initial = { title: '', content: '' }
+let opener: HTMLElement | null = null
+const dirty = computed(() => title.value !== initial.title || content.value !== initial.content)
+
+function loadDraft(memo: Memo) {
+  title.value = memo.title; content.value = memo.content
+  initial = { title: memo.title, content: memo.content }
+  error.value = ''; conflict.value = false
+}
+watch(() => props.memo, loadDraft, { immediate: true })
+function close() {
+  if (dirty.value && !window.confirm('有未保存的更改，确定离开吗？')) return
+  emit('close')
+  nextTick(() => opener?.focus())
+}
+function validate() {
+  const value = title.value.trim()
+  if (!value) return '请输入标题'
+  if (value.length > 200) return '标题最多 200 个字符'
+  return ''
+}
+async function save() {
+  error.value = validate(); if (error.value || saving.value || props.memo.deleted_at) return
+  saving.value = true; conflict.value = false
+  try {
+    const updated = await props.request(`/memos/${props.memo.id}`, { method: 'PATCH', body: JSON.stringify({ title: title.value.trim(), content: content.value, version: props.memo.version }) }) as Memo
+    loadDraft(updated); emit('saved', updated); emit('notice', '备忘录已保存')
+  } catch (reason) {
+    const status = (reason as { status?: number }).status
+    conflict.value = status === 409
+    error.value = conflict.value ? '版本冲突：草稿已保留，请重新载入后再保存。' : reason instanceof Error ? reason.message : '保存失败'
+  } finally { saving.value = false }
+}
+async function reload() {
+  try { const fresh = await props.request(`/memos/${props.memo.id}`) as Memo; loadDraft(fresh); emit('saved', fresh) } catch (reason) { error.value = reason instanceof Error ? reason.message : '重新载入失败' }
+}
+async function remove() {
+  if (!window.confirm(`把“${props.memo.title}”移到回收站？`)) return
+  error.value = ''
+  try {
+    await props.request(`/memos/${props.memo.id}`, { method: 'DELETE' })
+    emit('deleted', props.memo.id); emit('notice', '备忘录已移到回收站')
+  } catch (reason) { error.value = reason instanceof Error ? reason.message : '删除失败' }
+}
+async function restore() {
+  error.value = ''
+  try {
+    const restored = await props.request(`/memos/${props.memo.id}/restore`, { method: 'POST' }) as Memo
+    emit('restored', restored); emit('notice', '备忘录已恢复')
+  } catch (reason) { error.value = reason instanceof Error ? reason.message : '恢复失败' }
+}
+async function purge() {
+  if (!window.confirm(`永久删除“${props.memo.title}”？此操作无法撤销。`)) return
+  error.value = ''
+  try {
+    await props.request(`/memos/${props.memo.id}/purge`, { method: 'DELETE' })
+    emit('purged', props.memo.id); emit('notice', '备忘录已永久删除')
+  } catch (reason) { error.value = reason instanceof Error ? reason.message : '永久删除失败' }
+}
+function keydown(event: KeyboardEvent) {
+  if ((event.metaKey || event.ctrlKey) && event.key.toLowerCase() === 's') { event.preventDefault(); void save(); return }
+  if (event.key === 'Escape') { event.preventDefault(); close(); return }
+  if (!props.mobile || event.key !== 'Tab' || !root.value) return
+  const controls = [...root.value.querySelectorAll<HTMLElement>('button:not(:disabled),input:not(:disabled),textarea:not(:disabled)')]
+  if (!controls.length) return
+  const first = controls[0], last = controls.at(-1)!
+  if (event.shiftKey && document.activeElement === first) { event.preventDefault(); last.focus() }
+  else if (!event.shiftKey && document.activeElement === last) { event.preventDefault(); first.focus() }
+}
+function beforeUnload(event: BeforeUnloadEvent) { if (dirty.value) event.preventDefault() }
+onMounted(() => { opener = document.activeElement as HTMLElement; window.addEventListener('beforeunload', beforeUnload); nextTick(() => titleInput.value?.focus()) })
+onUnmounted(() => window.removeEventListener('beforeunload', beforeUnload))
+defineExpose({ dirty, requestClose: close })
+</script>
+
+<template>
+  <aside ref="root" class="memo-editor" role="dialog" :aria-modal="mobile ? 'true' : undefined" aria-labelledby="memo-editor-title" @keydown="keydown">
+    <header><span id="memo-editor-title">备忘录详情</span><button type="button" aria-label="关闭备忘录" @click="close"><X/></button></header>
+    <div class="memo-editor__fields">
+      <label>标题<input ref="titleInput" v-model="title" maxlength="200" aria-label="备忘录标题" :disabled="Boolean(memo.deleted_at)"></label>
+      <label>正文<textarea v-model="content" rows="16" aria-label="备忘录正文" placeholder="写点什么…" :disabled="Boolean(memo.deleted_at)"></textarea></label>
+      <p v-if="error" role="alert" class="memo-editor__error">{{ error }} <button v-if="conflict" class="memo-reload" type="button" @click="reload">重新载入</button></p>
+    </div>
+    <footer v-if="!memo.deleted_at"><button type="button" class="danger-text" @click="remove"><Trash2/>移到回收站</button><button type="button" class="primary-small memo-save" :disabled="saving || !dirty" @click="save">{{ saving ? '正在保存…' : '保存' }}</button></footer>
+    <footer v-else><button type="button" class="secondary" @click="restore"><ArchiveRestore/>恢复</button><button type="button" class="danger-button" @click="purge"><Trash2/>永久删除</button></footer>
+  </aside>
+</template>
diff --git a/frontend/src/components/MemoRow.test.ts b/frontend/src/components/MemoRow.test.ts
new file mode 100644
index 0000000..12844d4
--- /dev/null
+++ b/frontend/src/components/MemoRow.test.ts
@@ -0,0 +1,42 @@
+import { afterEach, describe, expect, it } from 'vitest'
+import { createApp, h, nextTick, ref } from 'vue'
+import MemoRow from './MemoRow.vue'
+
+const cleanups: Array<() => void> = []
+const memo = { id: 'm1', title: '旅行清单', excerpt: '护照\n  充电器   相机', version: 1, created_at: '2026-09-12T01:00:00Z', updated_at: '2026-09-12T02:00:00Z', deleted_at: null }
+
+afterEach(() => cleanups.splice(0).forEach((cleanup) => cleanup()))
+
+describe('MemoRow', () => {
+  it('renders a compact selectable row with plain excerpt and semantic update time', async () => {
+    const host = document.createElement('div'); document.body.append(host)
+    const selected: string[] = []
+    const app = createApp(() => h(MemoRow, { memo, active: true, onSelect: (id: string) => selected.push(id) }))
+    app.mount(host); cleanups.push(() => { app.unmount(); host.remove() }); await nextTick()
+    const button = host.querySelector('button')!
+    expect(button.classList.contains('active')).toBe(true)
+    expect(button.getAttribute('aria-current')).toBe('true')
+    expect(host.querySelector('.memo-row__excerpt')?.textContent).toBe('护照 充电器 相机')
+    expect(host.querySelector('time')?.getAttribute('datetime')).toBe(memo.updated_at)
+    button.click()
+    expect(selected).toEqual(['m1'])
+  })
+
+  it('updates the excerpt when the memo prop changes and preserves empty and whitespace formatting', async () => {
+    const host = document.createElement('div'); document.body.append(host)
+    const current = ref({ ...memo, excerpt: '' })
+    const app = createApp(() => h(MemoRow, { memo: current.value }))
+    app.mount(host); cleanups.push(() => { app.unmount(); host.remove() }); await nextTick()
+
+    const excerpt = () => host.querySelector('.memo-row__excerpt')?.textContent
+    expect(excerpt()).toBe('暂无正文')
+
+    current.value = { ...current.value, excerpt: '保存后\n  新摘要   正常' }
+    await nextTick()
+    expect(excerpt()).toBe('保存后 新摘要 正常')
+
+    current.value = { ...current.value, excerpt: ' \n\t  ' }
+    await nextTick()
+    expect(excerpt()).toBe('暂无正文')
+  })
+})
diff --git a/frontend/src/components/MemoRow.vue b/frontend/src/components/MemoRow.vue
new file mode 100644
index 0000000..dc9da61
--- /dev/null
+++ b/frontend/src/components/MemoRow.vue
@@ -0,0 +1,17 @@
+<script setup lang="ts">
+import { computed } from 'vue'
+
+export type MemoListItem = { id: string; title: string; excerpt: string; version: number; created_at: string; updated_at: string; deleted_at: string | null }
+const props = defineProps<{ memo: MemoListItem; active?: boolean }>()
+const emit = defineEmits<{ select: [id: string] }>()
+const excerpt = computed(() => props.memo.excerpt.replace(/\s+/g, ' ').trim())
+const updated = new Intl.DateTimeFormat('zh-CN', { month: 'numeric', day: 'numeric', hour: '2-digit', minute: '2-digit' }).format(new Date(props.memo.updated_at))
+</script>
+
+<template>
+  <button class="memo-row" :class="{ active }" :aria-current="active ? 'true' : undefined" @click="emit('select', memo.id)">
+    <strong>{{ memo.title }}</strong>
+    <span class="memo-row__excerpt">{{ excerpt || '暂无正文' }}</span>
+    <time :datetime="memo.updated_at">{{ updated }}</time>
+  </button>
+</template>
diff --git a/frontend/src/lib/mvp-utils.test.ts b/frontend/src/lib/mvp-utils.test.ts
index 77255fd..0ad959c 100644
--- a/frontend/src/lib/mvp-utils.test.ts
+++ b/frontend/src/lib/mvp-utils.test.ts
@@ -65,6 +65,8 @@ describe('MVP view utilities', () => {
     expect(readStoredNavigation(fakeStorage, 'dodo.navigation')).toEqual({ view: 'today', listId: '' })
     writeStoredNavigation(fakeStorage, 'dodo.navigation', 'tasks', 'list-2')
     expect(readStoredNavigation(fakeStorage, 'dodo.navigation')).toEqual({ view: 'tasks', listId: 'list-2' })
+    writeStoredNavigation(fakeStorage, 'dodo.navigation', 'memos', 'list-2')
+    expect(readStoredNavigation(fakeStorage, 'dodo.navigation')).toEqual({ view: 'memos', listId: 'list-2' })
     storage.set('dodo.navigation', JSON.stringify({ view: 'invalid', listId: 'list-2' }))
     expect(readStoredNavigation(fakeStorage, 'dodo.navigation')).toEqual({ view: 'today', listId: '' })
   })
diff --git a/frontend/src/lib/mvp-utils.ts b/frontend/src/lib/mvp-utils.ts
index 3269486..62316f0 100644
--- a/frontend/src/lib/mvp-utils.ts
+++ b/frontend/src/lib/mvp-utils.ts
@@ -1,7 +1,7 @@
 type BooleanStorage = Pick<Storage, 'getItem' | 'setItem'>
-type NavigationView = 'tasks' | 'today' | 'upcoming' | 'trash' | 'habits' | 'countdowns' | 'settings'
+type NavigationView = 'tasks' | 'today' | 'upcoming' | 'trash' | 'habits' | 'countdowns' | 'memos' | 'settings'
 type StoredNavigation = { view: NavigationView; listId: string }
-const NAVIGATION_VIEWS = new Set<NavigationView>(['tasks', 'today', 'upcoming', 'trash', 'habits', 'countdowns', 'settings'])
+const NAVIGATION_VIEWS = new Set<NavigationView>(['tasks', 'today', 'upcoming', 'trash', 'habits', 'countdowns', 'memos', 'settings'])
 
 export function readStoredNavigation(storage: BooleanStorage, key: string): StoredNavigation {
   try {
diff --git a/frontend/src/main.ts b/frontend/src/main.ts
index 19f71d9..dc9d5c7 100644
--- a/frontend/src/main.ts
+++ b/frontend/src/main.ts
@@ -1,6 +1,7 @@
 import { createApp } from 'vue'
 import App from './App.vue'
 import './style.css'
+import './memo.css'
 
 createApp(App).mount('#app')
 if ('serviceWorker' in navigator && import.meta.env.PROD) {
diff --git a/frontend/src/memo.css b/frontend/src/memo.css
new file mode 100644
index 0000000..b1a5942
--- /dev/null
+++ b/frontend/src/memo.css
@@ -0,0 +1,3 @@
+.memo-panel{position:relative;min-height:calc(100vh - 130px)}.memo-panel__main{display:grid;gap:14px}.memo-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px}.memo-scope{display:flex;gap:4px;padding:3px;border:1px solid var(--border-cream);border-radius:12px;background:var(--surface-raised)}.memo-scope button{min-height:44px;display:inline-flex;align-items:center;gap:6px;border:0;border-radius:9px;background:transparent;padding:0 13px}.memo-scope button[aria-selected="true"]{background:var(--accent-soft);color:#b7421e;font-weight:700}.memo-search{height:44px;min-width:min(320px,45%);display:flex;align-items:center;gap:8px;border:1px solid var(--border-cream);border-radius:11px;background:var(--surface-raised);padding:0 12px}.memo-search input{min-width:0;width:100%;border:0;outline:0;background:transparent;box-shadow:none}.memo-list{display:grid;gap:0;border:1px solid var(--border-cream);border-radius:var(--radius-list);background:var(--surface-raised);overflow:hidden}.memo-list.refreshing{opacity:.62}.memo-row{width:100%;min-height:76px;display:grid;grid-template-columns:minmax(0,1fr) auto;gap:4px 12px;border:0;background:var(--surface-raised);padding:12px 15px;text-align:left}.memo-row+.memo-row{border-top:1px solid var(--border-cream)}.memo-row:hover,.memo-row.active{background:#fff7eb}.memo-row strong{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.memo-row__excerpt{grid-column:1;display:-webkit-box;overflow:hidden;-webkit-line-clamp:2;-webkit-box-orient:vertical;color:var(--text-secondary);font-size:12px;line-height:1.45;white-space:normal}.memo-row time{grid-column:2;grid-row:1/3;align-self:center;color:var(--muted);font-size:11px}.memo-state{min-height:240px;display:grid;place-items:center;align-content:center;gap:9px;color:var(--muted);text-align:center}.memo-state svg{width:30px;height:30px;color:var(--accent)}.memo-load-more{justify-self:center;min-width:132px;min-height:44px}.memo-error,.memo-editor__error{color:var(--danger);background:#fff0ec;border-radius:10px;padding:10px 12px}.memo-editor{width:350px;position:fixed;z-index:42;right:0;top:0;bottom:0;display:flex;flex-direction:column;border-left:1px solid var(--border-cream);background:var(--surface-raised);box-shadow:var(--shadow-raised)}.memo-editor>header,.memo-editor>footer{min-height:64px;display:flex;align-items:center;justify-content:space-between;gap:10px;padding:10px 16px;border-bottom:1px solid var(--border-cream)}.memo-editor>header span{font-size:12px;font-weight:750;letter-spacing:.06em;color:var(--muted)}.memo-editor>header button{width:44px;height:44px;display:grid;place-items:center;border:0;border-radius:10px;background:transparent}.memo-editor__fields{flex:1;min-height:0;overflow:auto;display:grid;align-content:start;gap:14px;padding:18px}.memo-editor__fields label{display:grid;gap:7px;color:var(--text-secondary);font-size:12px;font-weight:700}.memo-editor__fields input,.memo-editor__fields textarea{width:100%;border:1px solid var(--border-cream);border-radius:11px;background:#fff;padding:12px;outline:0}.memo-editor__fields textarea{resize:vertical;line-height:1.65}.memo-editor__fields input:focus,.memo-editor__fields textarea:focus{border-color:var(--accent);box-shadow:0 0 0 3px var(--focus-ring)}.memo-editor>footer{border-top:1px solid var(--border-cream);border-bottom:0}.memo-editor>footer button{min-height:44px}.memo-editor-scrim{display:none}
+@media(max-width:930px){.memo-panel{min-height:calc(100dvh - 150px)}.memo-toolbar{align-items:stretch;flex-direction:column}.memo-search{width:100%;min-width:0}.memo-row{min-height:76px}.memo-editor-scrim{display:block;position:fixed;z-index:41;inset:0;background:var(--scrim)}.memo-editor{position:fixed;z-index:42;left:0;right:0;top:auto;bottom:0;width:100%;height:min(92dvh,820px);border:1px solid var(--border-cream);border-bottom:0;border-radius:22px 22px 0 0;transition:transform .22s ease}.memo-editor__fields{padding:16px}.memo-editor>footer{padding-bottom:max(10px,env(safe-area-inset-bottom))}}
+@media(prefers-reduced-motion:reduce){.memo-editor,.memo-row,.memo-list{transition:none!important}}
diff --git a/migrations/versions/0017_memos.py b/migrations/versions/0017_memos.py
new file mode 100644
index 0000000..4d8a781
--- /dev/null
+++ b/migrations/versions/0017_memos.py
@@ -0,0 +1,40 @@
+"""add independent memos
+
+Revision ID: 0017_memos
+Revises: 0016_recurrence_trigger_modes
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0017_memos"
+down_revision = "0016_recurrence_trigger_modes"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "memos",
+        sa.Column("id", sa.Uuid(), nullable=False),
+        sa.Column("user_id", sa.Uuid(), nullable=False),
+        sa.Column("title", sa.String(length=200), nullable=False),
+        sa.Column("content", sa.Text(), nullable=False, server_default=""),
+        sa.Column("version", sa.Integer(), nullable=False, server_default="1"),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
+        sa.ForeignKeyConstraint(["user_id"], ["users.id"], ondelete="CASCADE"),
+        sa.CheckConstraint("version >= 1", name="ck_memos_version_positive"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_memos_user_id", "memos", ["user_id"])
+    op.create_index(
+        "ix_memos_user_deleted_updated", "memos", ["user_id", "deleted_at", "updated_at", "id"]
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_memos_user_deleted_updated", table_name="memos")
+    op.drop_index("ix_memos_user_id", table_name="memos")
+    op.drop_table("memos")
diff --git a/tests/test_memos.py b/tests/test_memos.py
new file mode 100644
index 0000000..382fd95
--- /dev/null
+++ b/tests/test_memos.py
@@ -0,0 +1,281 @@
+from sqlalchemy import select
+
+from backend.auth import hash_password
+from backend.db import get_db
+from backend.models import Memo, TaskList, User
+
+
+def boot(client):
+    response = client.post(
+        "/api/v1/setup/initialize",
+        json={"username": "owner", "password": "correct horse battery staple"},
+    )
+    assert response.status_code == 201
+
+
+async def add_user(username: str):
+    db_gen = get_db()
+    db = await anext(db_gen)
+    try:
+        user = User(username=username, password_hash=hash_password("correct horse battery staple"))
+        db.add(user)
+        await db.flush()
+        db.add(TaskList(user_id=user.id, name="收集箱", is_inbox=True))
+        await db.commit()
+    finally:
+        await db_gen.aclose()
+
+
+def test_create_and_get_memo_trims_title_and_defaults_content(client):
+    boot(client)
+
+    created = client.post("/api/v1/memos", json={"title": "  第一篇  "})
+
+    assert created.status_code == 201
+    item = created.json()
+    assert item["title"] == "第一篇"
+    assert item["content"] == ""
+    assert item["version"] == 1
+    assert item["deleted_at"] is None
+    assert item["created_at"]
+    assert item["updated_at"]
+    assert client.get(f"/api/v1/memos/{item['id']}").json() == item
+
+
+def test_memo_title_validation(client):
+    boot(client)
+    assert client.post("/api/v1/memos", json={"title": "   "}).status_code == 422
+    assert client.post("/api/v1/memos", json={"title": "x" * 201}).status_code == 422
+
+
+def test_create_memo_validates_title_length_after_trimming(client):
+    boot(client)
+
+    one = client.post("/api/v1/memos", json={"title": "  x  "})
+    two_hundred = client.post("/api/v1/memos", json={"title": f"  {'x' * 200}  "})
+
+    assert one.status_code == 201
+    assert one.json()["title"] == "x"
+    assert two_hundred.status_code == 201
+    assert two_hundred.json()["title"] == "x" * 200
+    assert client.post("/api/v1/memos", json={"title": "   "}).status_code == 422
+    assert client.post("/api/v1/memos", json={"title": f"  {'x' * 201}  "}).status_code == 422
+
+
+def test_update_memo_validates_title_length_after_trimming(client):
+    boot(client)
+    memo = client.post("/api/v1/memos", json={"title": "Before"}).json()
+
+    one = client.patch(
+        f"/api/v1/memos/{memo['id']}", json={"title": "  x  ", "version": memo["version"]}
+    )
+    two_hundred = client.patch(
+        f"/api/v1/memos/{memo['id']}",
+        json={"title": f"  {'x' * 200}  ", "version": one.json()["version"]},
+    )
+
+    assert one.status_code == 200
+    assert one.json()["title"] == "x"
+    assert two_hundred.status_code == 200
+    assert two_hundred.json()["title"] == "x" * 200
+    assert client.patch(
+        f"/api/v1/memos/{memo['id']}", json={"title": "   ", "version": two_hundred.json()["version"]}
+    ).status_code == 422
+    assert client.patch(
+        f"/api/v1/memos/{memo['id']}",
+        json={"title": f"  {'x' * 201}  ", "version": two_hundred.json()["version"]},
+    ).status_code == 422
+
+
+def test_list_memos_scopes_searches_orders_paginates_and_builds_excerpt(client):
+    boot(client)
+    first = client.post(
+        "/api/v1/memos", json={"title": "Alpha note", "content": "  many\n words\tinside  "}
+    ).json()
+    second = client.post(
+        "/api/v1/memos", json={"title": "Second", "content": "alpha in body " + "x" * 200}
+    ).json()
+    third = client.post("/api/v1/memos", json={"title": "Third"}).json()
+    assert client.delete(f"/api/v1/memos/{third['id']}").status_code == 204
+
+    page = client.get("/api/v1/memos", params={"scope": "active", "q": "ALPHA", "page_size": 1})
+    assert page.status_code == 200
+    data = page.json()
+    assert data["total"] == 2
+    assert data["page"] == 1
+    assert data["page_size"] == 1
+    assert data["items"][0]["id"] == second["id"]
+    assert data["items"][0]["excerpt"] == ("alpha in body " + "x" * 105 + "…")
+    assert "content" not in data["items"][0]
+
+    second_page = client.get(
+        "/api/v1/memos", params={"scope": "active", "q": "alpha", "page": 2, "page_size": 1}
+    ).json()
+    assert second_page["items"][0]["id"] == first["id"]
+    assert second_page["items"][0]["excerpt"] == "many words inside"
+    assert [item["id"] for item in client.get("/api/v1/memos", params={"scope": "trash"}).json()["items"]] == [third["id"]]
+    assert client.get("/api/v1/memos", params={"page_size": 101}).status_code == 422
+
+
+def test_patch_uses_atomic_version_lock_and_deleted_memos_reject_edit(client):
+    boot(client)
+    memo = client.post("/api/v1/memos", json={"title": "Before", "content": "secret"}).json()
+
+    updated = client.patch(
+        f"/api/v1/memos/{memo['id']}",
+        json={"title": "  After  ", "content": "new secret", "version": 1},
+    )
+    assert updated.status_code == 200
+    assert updated.json()["title"] == "After"
+    assert updated.json()["content"] == "new secret"
+    assert updated.json()["version"] == 2
+    assert client.patch(
+        f"/api/v1/memos/{memo['id']}", json={"title": "stale", "version": 1}
+    ).status_code == 409
+    assert client.get(f"/api/v1/memos/{memo['id']}").json()["title"] == "After"
+
+    assert client.delete(f"/api/v1/memos/{memo['id']}").status_code == 204
+    assert client.patch(
+        f"/api/v1/memos/{memo['id']}", json={"content": "forbidden", "version": 2}
+    ).status_code == 409
+
+
+def test_patch_requires_version(client):
+    boot(client)
+    memo = client.post("/api/v1/memos", json={"title": "Versioned"}).json()
+    assert client.patch(f"/api/v1/memos/{memo['id']}", json={"title": "No version"}).status_code == 422
+
+
+def test_restore_and_purge_lifecycle(client):
+    boot(client)
+    active = client.post("/api/v1/memos", json={"title": "Active"}).json()
+    assert client.delete(f"/api/v1/memos/{active['id']}/purge").status_code == 409
+
+    assert client.delete(f"/api/v1/memos/{active['id']}").status_code == 204
+    deleted = client.get(f"/api/v1/memos/{active['id']}").json()
+    restored = client.post(f"/api/v1/memos/{active['id']}/restore")
+    assert restored.status_code == 200
+    assert restored.json()["deleted_at"] is None
+    assert restored.json()["updated_at"] > deleted["updated_at"]
+
+    assert client.delete(f"/api/v1/memos/{active['id']}").status_code == 204
+    assert client.delete(f"/api/v1/memos/{active['id']}/purge").status_code == 204
+    assert client.get(f"/api/v1/memos/{active['id']}").status_code == 404
+
+
+def test_cross_user_memo_access_is_uniform_404(client):
+    boot(client)
+    memo = client.post("/api/v1/memos", json={"title": "Owner only"}).json()
+    client.post("/api/v1/auth/logout")
+    client.portal.call(add_user, "other")
+    assert client.post(
+        "/api/v1/auth/login", json={"username": "other", "password": "correct horse battery staple"}
+    ).status_code == 200
+
+    assert client.get(f"/api/v1/memos/{memo['id']}").status_code == 404
+    assert client.patch(f"/api/v1/memos/{memo['id']}", json={"title": "x", "version": 1}).status_code == 404
+    assert client.delete(f"/api/v1/memos/{memo['id']}").status_code == 404
+    assert client.post(f"/api/v1/memos/{memo['id']}/restore").status_code == 404
+    assert client.delete(f"/api/v1/memos/{memo['id']}/purge").status_code == 404
+
+
+def test_memo_audit_records_actions_without_content(client):
+    boot(client)
+    memo = client.post("/api/v1/memos", json={"title": "Audit", "content": "TOP SECRET"}).json()
+    client.patch(
+        f"/api/v1/memos/{memo['id']}", json={"content": "NEW SECRET", "version": memo["version"]}
+    )
+    client.delete(f"/api/v1/memos/{memo['id']}")
+    client.post(f"/api/v1/memos/{memo['id']}/restore")
+    client.delete(f"/api/v1/memos/{memo['id']}")
+    client.delete(f"/api/v1/memos/{memo['id']}/purge")
+
+    logs = [row for row in client.get("/api/v1/audit-logs").json() if row["entity_type"] == "memo"]
+    assert [row["action"] for row in reversed(logs)] == ["create", "update", "delete", "restore", "delete", "purge"]
+    serialized = str(logs)
+    assert "TOP SECRET" not in serialized
+    assert "NEW SECRET" not in serialized
+
+
+def test_json_and_csv_backup_round_trip_memos_with_all_fields(client):
+    boot(client)
+    active = client.post("/api/v1/memos", json={"title": "Active", "content": "alpha"}).json()
+    active = client.patch(
+        f"/api/v1/memos/{active['id']}", json={"title": "Active 2", "version": 1}
+    ).json()
+    deleted = client.post("/api/v1/memos", json={"title": "Deleted", "content": "trash"}).json()
+    client.delete(f"/api/v1/memos/{deleted['id']}")
+
+    exported = client.get("/api/v1/export").json()
+    assert len(exported["memos"]) == 2
+    exported_active = next(row for row in exported["memos"] if row["title"] == "Active 2")
+    assert exported_active["content"] == "alpha"
+    assert exported_active["version"] == 2
+    assert exported_active["created_at"].replace("+00:00", "Z") == active["created_at"]
+    assert exported_active["updated_at"].replace("+00:00", "Z") == active["updated_at"]
+    assert exported_active["deleted_at"] is None
+
+    csv_backup = client.get("/api/v1/export.csv")
+    assert b"memos" in csv_backup.content
+    restored_csv = client.post(
+        "/api/v1/restore.csv?mode=replace",
+        files={"file": ("dodo-export.csv", csv_backup.content, "text/csv")},
+    )
+    assert restored_csv.status_code == 200
+    assert client.get("/api/v1/memos").json()["total"] == 1
+    assert client.get("/api/v1/memos", params={"scope": "trash"}).json()["total"] == 1
+    restored_active = client.get("/api/v1/memos").json()["items"][0]
+    detail = client.get(f"/api/v1/memos/{restored_active['id']}").json()
+    assert detail["title"] == "Active 2"
+    assert detail["content"] == "alpha"
+    assert detail["version"] == 2
+    assert detail["created_at"] == active["created_at"]
+    assert detail["updated_at"] == active["updated_at"]
+
+    client.post("/api/v1/memos", json={"title": "Extra"})
+    merged = client.post("/api/v1/restore?mode=merge", json=exported)
+    assert merged.status_code == 200
+    assert client.get("/api/v1/memos").json()["total"] == 2
+
+
+def test_restore_reassigns_foreign_memo_to_current_user(client):
+    boot(client)
+    exported = client.get("/api/v1/export").json()
+    client.portal.call(add_user, "other")
+
+    async def add_foreign_memo():
+        db_gen = get_db()
+        db = await anext(db_gen)
+        try:
+            other = await db.scalar(select(User).where(User.username == "other"))
+            memo = Memo(user_id=other.id, title="Foreign")
+            db.add(memo)
+            await db.commit()
+            return str(memo.id)
+        finally:
+            await db_gen.aclose()
+
+    foreign_id = client.portal.call(add_foreign_memo)
+    exported["memos"] = [{
+        "id": foreign_id,
+        "title": "Imported",
+        "content": "owned here",
+        "version": 3,
+        "created_at": "2026-01-01T00:00:00+00:00",
+        "updated_at": "2026-01-02T00:00:00+00:00",
+        "deleted_at": None,
+    }]
+    response = client.post("/api/v1/restore?mode=merge", json=exported)
+    assert response.status_code == 200
+    imported = client.get("/api/v1/memos", params={"q": "Imported"}).json()["items"][0]
+    assert imported["id"] != foreign_id
+    assert client.get(f"/api/v1/memos/{imported['id']}").json()["content"] == "owned here"
+    assert client.post("/api/v1/restore?mode=merge", json=exported).status_code == 200
+    assert client.get("/api/v1/memos", params={"q": "Imported"}).json()["total"] == 1
+
+
+def test_legacy_backup_without_memos_still_restores(client):
+    boot(client)
+    backup = client.get("/api/v1/export").json()
+    backup.pop("memos", None)
+    assert client.post("/api/v1/restore?mode=replace", json=backup).status_code == 200
diff --git a/tests/test_migration_memos.py b/tests/test_migration_memos.py
new file mode 100644
index 0000000..fdfc90a
--- /dev/null
+++ b/tests/test_migration_memos.py
@@ -0,0 +1,36 @@
+import os
+import sqlite3
+import subprocess
+from pathlib import Path
+
+
+def run_alembic(repo: Path, database: Path, *args: str) -> subprocess.CompletedProcess[str]:
+    env = os.environ.copy()
+    env["DODO_DATABASE_URL"] = f"sqlite+aiosqlite:///{database}"
+    return subprocess.run(
+        ["uv", "run", "alembic", *args], cwd=repo, env=env, text=True, capture_output=True, check=False
+    )
+
+
+def test_memos_migration_upgrade_and_downgrade(tmp_path: Path):
+    repo = Path(__file__).resolve().parents[1]
+    database = tmp_path / "migration.sqlite3"
+    assert run_alembic(repo, database, "upgrade", "0016_recurrence_trigger_modes").returncode == 0
+
+    upgraded = run_alembic(repo, database, "upgrade", "0017_memos")
+    assert upgraded.returncode == 0, upgraded.stderr
+    with sqlite3.connect(database) as connection:
+        columns = {row[1]: row for row in connection.execute("PRAGMA table_info(memos)")}
+        assert set(columns) == {"id", "user_id", "title", "content", "version", "created_at", "updated_at", "deleted_at"}
+        assert columns["title"][3] == 1
+        assert columns["content"][3] == 1
+        assert columns["version"][3] == 1
+        indexes = {row[1] for row in connection.execute("PRAGMA index_list(memos)")}
+        assert "ix_memos_user_deleted_updated" in indexes
+
+    downgraded = run_alembic(repo, database, "downgrade", "0016_recurrence_trigger_modes")
+    assert downgraded.returncode == 0, downgraded.stderr
+    with sqlite3.connect(database) as connection:
+        assert connection.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' AND name='memos'"
+        ).fetchone() is None