Add reloadFromState() for clean engine reset on layout switch

server/playlist.js

@@ -96,6 +96,18 @@ class Playlist {
     return this.getConfig();
   }
 
+  /* Re-read the persisted playlist config from state (used after a layout load
+   * swaps playlist.live.json) and do the same clean reset as setConfig. */
+  reloadFromState() {
+    const saved = this.state.getPlaylistConfig(Playlist.defaults());
+    this.cfg = Playlist.migrate({ ...Playlist.defaults(), ...saved });
+    for (const uid of [...this.active.keys()]) this.despawn(uid);
+    this.trackState.clear();
+    this.tick();
+    this.broadcast({ type: 'active', ghosts: this.activeSnapshot() });
+    return this.getConfig();
+  }
+
   allGhosts() { return this.state.getGhosts().ghosts; }
 
   /* Ghosts a track may use, minus those pinned as residents. */