fix: stable WS client ID + presentation name for poster modal title

- Generate and persist crypto.randomUUID() as controller_client_id on first
  launcher load (events_loc is persisted so it survives page reloads).
  Previously fell back to Date.now() on every reload.
- ae_open: handler now resolves presentation name via Dexie lookup chain:
  file.for_id -> presentation.name, falling back to file.filename.
  Remote modal now shows the presentation title instead of raw filename.

src/routes/events/[event_id]/(launcher)/launcher/+layout.svelte

@@ -78,6 +78,15 @@
         };
     }
 
+    // Generate a stable per-device client ID on first load and persist it.
+    // events_loc is backed by svelte-persisted-store (localStorage) so this
+    // survives page reloads. Without this, client_id falls back to Date.now()
+    // inside element_websocket_v3 — a new ID on every reload, which breaks
+    // direct-target WS messages and doesn't match V3 Vision ID expectations.
+    if (!$events_loc.launcher.controller_client_id) {
+        $events_loc.launcher.controller_client_id = crypto.randomUUID();
+    }
+
     // Unified Selection Sync (Refactored 2026-02-11)
     // WHY: We track URL params directly to ensure the UI reacts instantly to navigation.
     // We use untrack for store writes to prevent circular dependency loops.
@@ -342,10 +351,16 @@
                     $events_sess.launcher.modal__open_event_file_id = obj_id;
                     // Look up the file object from Dexie so the modal can render the image.
                     // The remote device has no event_file_obj in scope — only the ID was sent over WS.
-                    db_events.file.get(obj_id).then((file_obj: any) => {
+                    // Also look up the parent presentation to use its name as the modal title
+                    // (cleaner for the LCD display than a raw filename).
+                    db_events.file.get(obj_id).then(async (file_obj: any) => {
                         if (file_obj) {
                             $events_sess.launcher.modal__event_file_obj = file_obj;
-                            $events_sess.launcher.modal__title = file_obj.filename ?? '';
+                            const presentation = file_obj.for_id
+                                ? await db_events.presentation.get(file_obj.for_id)
+                                : null;
+                            $events_sess.launcher.modal__title =
+                                presentation?.name ?? file_obj.filename ?? '';
                         }
                     });
                 }