feat(launcher): implement device heartbeat and background sync engine

- Hardened 'find_object_id' in Dexie to support 'event_' prefixed IDs.
- Implemented singleton 'LauncherBackgroundSync' in root launcher layout.
- Added V3-compliant heartbeat and room refresh cycles.
- Fixed redundant component imports and Skeleton UI prop errors.
- Added 'inc_file_li' support to event API loader.

src/routes/events/[event_id]/+page.svelte

@@ -422,7 +422,7 @@ max-w-max -->
 <!-- lg:bg-green-100
     xl:bg-green-200 -->
 
-<Event_page_menu {data} {lq__event_obj} />
+<Event_page_menu {lq__event_obj} />
 
 {#if !$lq__event_obj}
     <div>