Add model selection, dashboard chat input, and model warming

- Add GET /api/chat/ps and POST /api/chat/warm endpoints for hot model
  visibility and pre-loading
- Extend PATCH /api/chat/conversations/:id to accept model in addition
  to title
- Add ModelSelector component with hot/cold indicators from Ollama /api/ps
- Add DashboardChatInput component (model selector + note picker + textarea)
  replacing the simple "New Chat" button on the dashboard
- Add model selector dropdown to ChatView header, persisted per-conversation
- Warm default model on dashboard mount via fire-and-forget background task
- Configure Ollama with OLLAMA_MAX_LOADED_MODELS=2 and OLLAMA_KEEP_ALIVE=30m
- Always-visible edit buttons on NoteCard/TaskCard (remove hover-only behavior)

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

src/fabledassistant/services/chat.py

@@ -103,8 +103,11 @@ async def delete_conversation(user_id: int, conversation_id: int) -> bool:
         return True
 
 
-async def update_conversation_title(
-    user_id: int, conversation_id: int, title: str
+async def update_conversation(
+    user_id: int,
+    conversation_id: int,
+    title: str | None = None,
+    model: str | None = None,
 ) -> Conversation | None:
     async with async_session() as session:
         result = await session.execute(
@@ -116,13 +119,22 @@ async def update_conversation_title(
         conv = result.scalars().first()
         if conv is None:
             return None
-        conv.title = title
+        if title is not None:
+            conv.title = title
+        if model is not None:
+            conv.model = model
         conv.updated_at = datetime.now(timezone.utc)
         await session.commit()
         await session.refresh(conv)
         return conv
 
 
+async def update_conversation_title(
+    user_id: int, conversation_id: int, title: str
+) -> Conversation | None:
+    return await update_conversation(user_id, conversation_id, title=title)
+
+
 async def add_message(
     conversation_id: int,
     role: str,