Merge branch 'main' into dev

Bring main's maintainer-curated work (cookbook scheduler, calendar rendering/sync, settings polish, agent debug loop) into dev so dev is a superset of main (resolves the dev/main drift, #2543).

app.py

@@ -1062,6 +1062,16 @@ async def _startup_event():
                 logger.warning(f"Nightly skill audit failed: {e}")
 
     _startup_tasks.append(asyncio.create_task(_skill_audit_nightly_loop()))
+
+    # Cookbook serve lifecycle — kills scheduler-launched serves whose
+    # window-end has passed. Paired with the cookbook_serve builtin
+    # action; both are no-ops unless a scheduled task actually launches
+    # something with end_after_min set. Removing this line + the
+    # cookbook_serve entry in BUILTIN_ACTIONS + src/cookbook_serve_lifecycle.py
+    # removes the feature.
+    from src.cookbook_serve_lifecycle import cookbook_serve_lifecycle_loop
+    _startup_tasks.append(asyncio.create_task(cookbook_serve_lifecycle_loop()))
+
     logger.info("Application startup complete")
 
 async def _shutdown_event():