perf: preload and cache countdowns

frontend/src/CountdownPanel.vue

@@ -2,7 +2,7 @@
 import { computed, nextTick, onBeforeUnmount, onMounted, ref } from 'vue'
 import { Archive, ArchiveRestore, CalendarHeart, ChevronDown, Pencil, Pin, Trash2, X } from 'lucide-vue-next'
 import { csrfHeader } from './lib/csrf'
-import { calendarModeLabel, countdownDayText, countdownKindLabel, dateKey, formatApiErrorDetail } from './lib/mvp-utils'
+import { calendarModeLabel, countdownDayText, countdownKindLabel, dateKey, formatApiErrorDetail, readCountdownCache, writeCountdownCache } from './lib/mvp-utils'
 
 type Countdown = {
   id: string; title: string; event_date: string; display_date: string; kind: 'countdown'|'anniversary'|'birthday'
@@ -99,7 +99,25 @@ async function request(path:string, options:RequestInit={}) {
   return response.status === 204 ? null : response.json()
 }
 async function safe(work:()=>Promise<void>) { busy.value=true; error.value=''; try { await work() } catch(reason) { error.value=reason instanceof Error ? reason.message : '请求失败' } finally { busy.value=false } }
-async function load() { await safe(async()=>{ const [a,b]=await Promise.all([request('/countdowns'),request('/countdowns?archived=true')]); items.value=a; archived.value=b }) }
+async function load() {
+  const cached = readCountdownCache<Countdown>()
+  if (cached) { items.value=cached.items; archived.value=cached.archived }
+  if (!cached) busy.value=true
+  error.value=''
+  try {
+    const active = await request('/countdowns') as Countdown[]
+    items.value=active
+    writeCountdownCache(items.value, archived.value)
+    busy.value=false
+    const archivedItems = await request('/countdowns?archived=true') as Countdown[]
+    archived.value=archivedItems
+    writeCountdownCache(items.value, archived.value)
+  } catch(reason) {
+    error.value=reason instanceof Error ? reason.message : '请求失败'
+  } finally {
+    busy.value=false
+  }
+}
 function edit(item:Countdown) {
   detailItem.value=null
   editingId.value=item.id