Add persistent context sidebar, note title fix, and expanded tool suite

Context sidebar + note title:
- ChatView: replace ephemeral context pills with a persistent right-panel sidebar;
  auto-found notes accumulate across turns; attached note shows with pin icon;
  × button excludes a note from future auto-search; hidden on mobile
- routes/chat.py: batch-fetch note titles via get_notes_by_ids() and inject
  context_note_title into each message dict at conversation load time
- notes.py: add get_notes_by_ids() batch fetch helper
- types/chat.ts: add context_note_title field to Message interface
- stores/chat.ts: sendMessage accepts optional 5th arg contextNoteTitle,
  included in optimistic user message
- ChatMessage.vue: context badge shows note title instead of 'Note #N'

Expanded LLM tool suite (all with intent router rules + ToolCallCard display):
- delete_note / delete_task: permanent delete with user confirmation (write tool),
  type-safe (refuse to delete wrong type), clears note context cache on success
- get_note: fetch full note body by query (search_notes returns only 200-char preview)
- list_notes: browse notes by recency/keyword/tags with limit; notes only
- update_note: add tags + tag_mode (replace/add/remove) parameters
- search_notes: add optional type filter ("note" | "task")
- search_todos (CalDAV): keyword-filter todos, companion to list_todos
- caldav.py: add search_todos() built on top of list_todos()
- generation_task.py: register new tools in _WRITE_TOOLS, _TOOL_LABELS, _TOOL_ACTIONS
- llm.py: update available actions list and guidance in system prompt
- intent.py: routing rules for all new tools

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

src/fabledassistant/services/notes.py

@@ -250,6 +250,17 @@ async def search_notes_for_context(
         return list(result.scalars().all())
 
 
+async def get_notes_by_ids(user_id: int, note_ids: list[int]) -> dict[int, Note]:
+    """Batch fetch notes by ID list. Returns {note_id: Note}."""
+    if not note_ids:
+        return {}
+    async with async_session() as session:
+        result = await session.execute(
+            select(Note).where(Note.user_id == user_id, Note.id.in_(note_ids))
+        )
+        return {n.id: n for n in result.scalars().all()}
+
+
 async def get_backlinks(user_id: int, note_id: int) -> list[dict]:
     note = await get_note(user_id, note_id)
     if note is None: