feat: session naming with unique titles, auto-lineage, rich listing, resume by name

- Schema v4: unique title index, migration from v2/v3
- set/get/resolve session titles with uniqueness enforcement
- Auto-lineage: context compression auto-numbers titles (Task -> Task #2 -> Task #3)
- resolve_session_by_title: auto-latest finds most recent continuation
- list_sessions_rich: preview (first 60 chars) + last_active timestamp
- CLI: -c accepts optional name arg (hermes -c 'my project')
- CLI: /title command with deferred mode (set before session exists)
- CLI: sessions list shows Title, Preview, Last Active, ID
- 27 new tests (1844 total passing)

run_agent.py

@@ -2484,6 +2484,8 @@ class AIAgent:
 
         if self._session_db:
             try:
+                # Propagate title to the new session with auto-numbering
+                old_title = self._session_db.get_session_title(self.session_id)
                 self._session_db.end_session(self.session_id, "compression")
                 old_session_id = self.session_id
                 self.session_id = f"{datetime.now().strftime('%Y%m%d_%H%M%S')}_{uuid.uuid4().hex[:6]}"
@@ -2493,6 +2495,13 @@ class AIAgent:
                     model=self.model,
                     parent_session_id=old_session_id,
                 )
+                # Auto-number the title for the continuation session
+                if old_title:
+                    try:
+                        new_title = self._session_db.get_next_title_in_lineage(old_title)
+                        self._session_db.set_session_title(self.session_id, new_title)
+                    except (ValueError, Exception) as e:
+                        logger.debug("Could not propagate title on compression: %s", e)
                 self._session_db.update_system_prompt(self.session_id, new_system_prompt)
             except Exception as e:
                 logger.debug("Session DB compression split failed: %s", e)