Order conversations by recency and auto-name from first message

Conversations are now returned sorted by most recently updated first.
New conversations are named using the first 100 characters of the
user's initial message instead of a username+timestamp placeholder.

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

blueprints/conversation/logic.py

@@ -19,6 +19,12 @@ async def add_message_to_conversation(
     image_key: str | None = None,
 ) -> ConversationMessage:
     print(conversation, message, speaker)
+
+    # Name the conversation after the first user message
+    if speaker == "user" and not await conversation.messages.all().exists():
+        conversation.name = message[:100]
+        await conversation.save()
+
     message = await ConversationMessage.create(
         text=message,
         speaker=speaker,