fix: poster WS remote control - push open and resolve file obj

- launcher_file_cont: poster 'Open Poster' click now sends ae_open:event_file
  command to remote display when controller=local_push and WS is connected
- +layout.svelte handle_ws_recv: ae_open: handler now looks up the file obj
  from Dexie after setting modal__open_event_file_id, so the remote modal
  has the hosted_file_id needed to render the poster image (was showing
  'No image selected' on remote device)

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

@@ -265,6 +265,11 @@
                     if (!modal__title) modal__title = event_file_obj.filename;
                     $events_slct.event_file_id = event_file_id;
                     $events_slct.event_file_obj = event_file_obj;
+                    // Push the open command to the remote display when in local_push mode
+                    if ($events_loc.launcher.controller == 'local_push' && $events_sess.launcher.ws_connect_status == 'connected') {
+                        $events_sess.launcher.controller_cmd = `ae_open:event_file=${event_file_id}`;
+                        $events_sess.launcher.controller_trigger_send = true;
+                    }
                 }}
             >
                 {#snippet label()}