feat(stalker): discover portal connection on edit

libs/shared/interfaces/src/lib/playlist-meta.type.ts

@@ -35,3 +35,23 @@ export type PlaylistMeta = Pick<
     | 'stalkerSignature1'
     | 'stalkerSignature2'
 >;
+
+export interface StalkerPlaylistSessionMetadata {
+    stalkerToken: string;
+    stalkerSessionIdentity?: string;
+    stalkerWatchdogTimeout?: number;
+    stalkerTimeslot?: number;
+    stalkerAccountInfo?: Playlist['stalkerAccountInfo'];
+}
+
+/**
+ * Metadata update accepted by the persistence boundary.
+ *
+ * `stalkerSessionPatch` is transient: absence preserves the negotiated
+ * session, `null` clears it, and an object fully replaces it. The patch is
+ * projected onto the existing flat playlist fields and is never persisted as
+ * its own database or backup property.
+ */
+export interface PlaylistMetaUpdate extends PlaylistMeta {
+    stalkerSessionPatch?: StalkerPlaylistSessionMetadata | null;
+}