fix: load tasks by selected list

backend/main.py

@@ -464,6 +464,8 @@ async def create_task(
 @app.get("/api/v1/tasks", response_model=TaskPage)
 async def list_tasks(
     q: str | None = None,
+    list_id: UUID | None = None,
+    completed: bool | None = None,
     cursor: str | None = None,
     limit: int = Query(default=50, ge=1, le=100),
     user: User = Depends(current_user),
@@ -472,6 +474,11 @@ async def list_tasks(
     query = select(Task).where(
         Task.user_id == user.id, Task.deleted_at.is_(None), Task.parent_id.is_(None)
     )
+    if list_id is not None:
+        await _owned_list(db, user.id, list_id)
+        query = query.where(Task.list_id == list_id)
+    if completed is not None:
+        query = query.where(Task.completed.is_(completed))
     if q:
         pattern = f"%{q}%"
         tag_match = exists(