feat: auto-generate session titles after first exchange

After the first user→assistant exchange, Hermes now generates a short
descriptive session title via the auxiliary LLM (compression task config).
Title generation runs in a background thread so it never delays the
user-facing response.

Key behaviors:
- Fires only on the first 1-2 exchanges (checks user message count)
- Skips if a title already exists (user-set titles are never overwritten)
- Uses call_llm with compression task config (cheapest/fastest model)
- Truncates long messages to keep the title generation request small
- Cleans up LLM output: strips quotes, 'Title:' prefixes, enforces 80 char max
- Works in both CLI and gateway (Telegram/Discord/etc.)

Also updates /title (no args) to show the session ID alongside the title
in both CLI and gateway.

Implements #1426

gateway/run.py

@@ -3328,12 +3328,12 @@ class GatewayRunner:
             except ValueError as e:
                 return f"⚠️ {e}"
         else:
-            # Show the current title
+            # Show the current title and session ID
             title = self._session_db.get_session_title(session_id)
             if title:
-                return f"📌 Session title: **{title}**"
+                return f"📌 Session: `{session_id}`\nTitle: **{title}**"
             else:
-                return "No title set. Usage: `/title My Session Name`"
+                return f"📌 Session: `{session_id}`\nNo title set. Usage: `/title My Session Name`"
 
     async def _handle_resume_command(self, event: MessageEvent) -> str:
         """Handle /resume command — switch to a previously-named session."""
@@ -4511,6 +4511,21 @@ class GatewayRunner:
 
             effective_session_id = getattr(agent, 'session_id', session_id) if agent else session_id
 
+            # Auto-generate session title after first exchange (non-blocking)
+            if final_response and self._session_db:
+                try:
+                    from agent.title_generator import maybe_auto_title
+                    all_msgs = result_holder[0].get("messages", []) if result_holder[0] else []
+                    maybe_auto_title(
+                        self._session_db,
+                        effective_session_id,
+                        message,
+                        final_response,
+                        all_msgs,
+                    )
+                except Exception:
+                    pass
+
             return {
                 "final_response": final_response,
                 "last_reasoning": result.get("last_reasoning"),