feat: complete task management workflow

backend/models.py

@@ -1,7 +1,7 @@
 from datetime import UTC, datetime
 from uuid import UUID
 
-from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text
+from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text, UniqueConstraint
 from sqlalchemy.orm import Mapped, mapped_column
 from uuid_utils import uuid7
 
@@ -47,6 +47,7 @@ class Folder(Base):
     name: Mapped[str] = mapped_column(String(120))
     position: Mapped[int] = mapped_column(Integer, default=0)
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)
+    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
 
 
 class TaskList(Base):
@@ -58,6 +59,23 @@ class TaskList(Base):
     is_inbox: Mapped[bool] = mapped_column(Boolean, default=False)
     position: Mapped[int] = mapped_column(Integer, default=0)
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)
+    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+
+
+class Tag(Base):
+    __tablename__ = "tags"
+    __table_args__ = (UniqueConstraint("user_id", "name", name="uq_tags_user_id_name"),)
+    id: Mapped[UUID] = mapped_column(primary_key=True, default=new_id)
+    user_id: Mapped[UUID] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), index=True)
+    name: Mapped[str] = mapped_column(String(80))
+    color: Mapped[str] = mapped_column(String(32), default="#f15a29")
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)
+
+
+class TaskTag(Base):
+    __tablename__ = "task_tags"
+    task_id: Mapped[UUID] = mapped_column(ForeignKey("tasks.id", ondelete="CASCADE"), primary_key=True)
+    tag_id: Mapped[UUID] = mapped_column(ForeignKey("tags.id", ondelete="CASCADE"), primary_key=True)
 
 
 class Task(Base):