Merge tasks into notes: a task is just a note with task attributes

A task is now a note with status/priority/due_date columns set (status IS NOT NULL).
This eliminates the separate tasks table, companion note system, cascade deletes,
bidirectional title sync, and _skip_cascade flags.

Migration (0004):
- Add status, priority, due_date columns to notes table
- Migrate task data from companion notes and orphan tasks
- Drop tasks table and old enum types

Backend:
- models/note.py: Add TaskStatus/TaskPriority enums, task columns, is_task property
- models/task.py: Deleted (merged into note.py)
- models/__init__.py: Re-export enums from note.py, remove Task import
- services/notes.py: Remove companion/cascade logic, add is_task filter,
  convert_note_to_task, convert_task_to_note, simplified backlinks
- services/tasks.py: Rewritten as thin wrappers around notes service
- routes/notes.py: Add is_task filter (default false), task fields in CRUD,
  convert-to-note endpoint
- routes/tasks.py: description→body (with fallback), remove note_id filter

Frontend:
- types/note.ts: Add TaskStatus, TaskPriority, task fields to Note interface
- types/task.ts: Task is now a re-export alias for Note
- stores/notes.ts: Simplify convertToTask, add convertToNote
- stores/tasks.ts: description→body in createTask/updateTask
- TaskEditorView: description→body, remove companion note UI
- TaskViewerView: description→body, remove companion note link, add Convert to Note
- NoteViewerView: Remove companion task UI, simplify convert-to-task
- TaskCard: description→body, non-null assertions for status/priority

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/fabledassistant/routes/tasks.py

@@ -2,7 +2,7 @@ from datetime import date
 
 from quart import Blueprint, jsonify, request
 
-from fabledassistant.models.task import TaskPriority, TaskStatus
+from fabledassistant.models.note import TaskPriority, TaskStatus
 from fabledassistant.services.tasks import (
     create_task,
     delete_task,
@@ -21,7 +21,6 @@ async def list_tasks_route():
     tag = request.args.getlist("tag")
     status = request.args.get("status")
     priority = request.args.get("priority")
-    note_id = request.args.get("note_id", type=int)
     sort = request.args.get("sort", "updated_at")
     order = request.args.get("order", "desc")
     limit = request.args.get("limit", 50, type=int)
@@ -32,7 +31,6 @@ async def list_tasks_route():
         tags=tag or None,
         status=status,
         priority=priority,
-        note_id=note_id,
         sort=sort,
         order=order,
         limit=limit,
@@ -44,21 +42,21 @@ async def list_tasks_route():
 @tasks_bp.route("", methods=["POST"])
 async def create_task_route():
     data = await request.get_json()
-    description = data.get("description", "")
-    tags = extract_tags(description)
+    body = data.get("body", "") or data.get("description", "")
+    tags = extract_tags(body)
 
     due_date = None
     if data.get("due_date"):
         due_date = date.fromisoformat(data["due_date"])
 
-    status = TaskStatus(data["status"]) if "status" in data else TaskStatus.todo
+    status = TaskStatus(data["status"]).value if "status" in data else TaskStatus.todo.value
     priority = (
-        TaskPriority(data["priority"]) if "priority" in data else TaskPriority.none
+        TaskPriority(data["priority"]).value if "priority" in data else TaskPriority.none.value
     )
 
     task = await create_task(
         title=data.get("title", ""),
-        description=description,
+        body=body,
         status=status,
         priority=priority,
         due_date=due_date,
@@ -79,17 +77,23 @@ async def get_task_route(task_id: int):
 async def update_task_route(task_id: int):
     data = await request.get_json()
     fields = {}
-    for key in ("title", "description", "status", "priority"):
+    for key in ("title", "status", "priority"):
         if key in data:
             fields[key] = data[key]
 
+    # Accept both "body" and "description" (prefer body)
+    if "body" in data:
+        fields["body"] = data["body"]
+    elif "description" in data:
+        fields["body"] = data["description"]
+
     if "due_date" in data:
         fields["due_date"] = (
             date.fromisoformat(data["due_date"]) if data["due_date"] else None
         )
 
-    if "description" in fields:
-        fields["tags"] = extract_tags(fields["description"])
+    if "body" in fields:
+        fields["tags"] = extract_tags(fields["body"])
 
     task = await update_task(task_id, **fields)
     if task is None: