UI polish pass: word count, slash commands, task lists, graph peek, bulk delete, export

- WordCount component (toggle words/chars vs read time, persisted mode)
- TipTap: TaskList/TaskItem extensions, slash command menu (H1-H3, lists, code, quote, task)
- Markdown serializer: task list → `- [ ]` / `- [x]` roundtrip
- GraphView: slide-in peek panel for note/task nodes (body, tags, linked nodes); tag nodes still navigate
- ChatView: bulk-select conversations with two-click confirm delete + chat retention policy (default 90d)
- NoteEditorView: pill tab bar with animated edit/preview toggle + WordCount in toolbar
- WorkspaceNoteEditor: inline search with tag matching, inline new-note creation, WordCount
- WorkspaceTaskPanel: task body rendered in slide-over + Edit link
- Settings: data export (Markdown ZIP / JSON) via GET /api/export
- Accessibility: skip-to-content link, aria-labels on all icon-only buttons
- Fix: export route used non-existent fabledassistant.database — corrected to async_session()
- Fix: ToolCallRecord.status type now includes "running" (was causing TS build error)
- Dockerfile: upgrade npm to latest before install to suppress major-version notice
- npm audit fix: patched minimatch (ReDoS) and rollup (path traversal) — 0 vulnerabilities

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

src/fabledassistant/services/chat.py

@@ -1,7 +1,7 @@
 import logging
-from datetime import datetime, timezone
+from datetime import datetime, timedelta, timezone
 
-from sqlalchemy import func, select
+from sqlalchemy import func, select, delete as sa_delete
 from sqlalchemy.orm import selectinload
 
 from fabledassistant.models import async_session
@@ -103,6 +103,35 @@ async def delete_conversation(user_id: int, conversation_id: int) -> bool:
         return True
 
 
+async def bulk_delete_conversations(user_id: int, ids: list[int]) -> int:
+    """Delete multiple conversations by ID for a user. Returns count deleted."""
+    if not ids:
+        return 0
+    async with async_session() as session:
+        result = await session.execute(
+            sa_delete(Conversation)
+            .where(Conversation.user_id == user_id, Conversation.id.in_(ids))
+            .returning(Conversation.id)
+        )
+        await session.commit()
+        return len(result.fetchall())
+
+
+async def cleanup_old_conversations(user_id: int, days: int) -> int:
+    """Delete conversations older than `days` days. Returns count deleted."""
+    if days <= 0:
+        return 0
+    cutoff = datetime.now(timezone.utc) - timedelta(days=days)
+    async with async_session() as session:
+        result = await session.execute(
+            sa_delete(Conversation)
+            .where(Conversation.user_id == user_id, Conversation.updated_at < cutoff)
+            .returning(Conversation.id)
+        )
+        await session.commit()
+        return len(result.fetchall())
+
+
 async def update_conversation(
     user_id: int,
     conversation_id: int,