fix(workspace): keep the overlay delay while another playlist refreshes

Refresh preparation skipped the cached-load delay for any playlist, so
opening a cached portal while another playlist prepared a refresh still
flashed the overlay. Only preparation of the shown playlist (any on the
dashboard) now shows it at once.

Also words the J2 layout-shift history from #1895 in the past tense: the
cached-load overlay no longer mounts on a J2 click.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/workspace/shell/feature/src/lib/workspace-shell/services/workspace-shell-xtream-import.service.spec.ts

@@ -153,6 +153,16 @@ describe('WorkspaceShellXtreamImportService', () => {
             expect(service.showXtreamImportOverlay()).toBe(true);
         });
 
+        it('keeps the delay while another playlist prepares a refresh', () => {
+            refreshPreparation.set({ playlistId: 'other-playlist' });
+            activeImportSessionId.set('session-1');
+            advance(0);
+            expect(service.showXtreamImportOverlay()).toBe(false);
+
+            advance(XTREAM_LOCAL_LOAD_OVERLAY_DELAY_MS);
+            expect(service.showXtreamImportOverlay()).toBe(true);
+        });
+
         it('shows the overlay at once while a refresh prepares the playlist', () => {
             refreshPreparation.set({ playlistId: 'portal-1' });
             expect(service.showXtreamImportOverlay()).toBe(true);

libs/workspace/shell/feature/src/lib/workspace-shell/services/workspace-shell-xtream-import.service.ts

@@ -109,15 +109,25 @@ export class WorkspaceShellXtreamImportService {
 
     /**
      * Remote imports (the store flags `isImporting` for every phase except
-     * `loading-cached`) and refresh preparation show the overlay at once. A
-     * session that has only read the saved catalog so far waits
-     * `XTREAM_LOCAL_LOAD_OVERLAY_DELAY_MS`, so a warm open never flashes it.
+     * `loading-cached`) and refresh preparation of the shown playlist (any
+     * on the dashboard) show the overlay at once. A session that has only
+     * read the saved catalog so far waits `XTREAM_LOCAL_LOAD_OVERLAY_DELAY_MS`,
+     * so a warm open never flashes it, even while another playlist prepares
+     * a refresh.
      */
-    private readonly isOverlayImmediate = computed(
-        () =>
-            Boolean(this.refreshPreparation()) ||
-            this.xtreamStore.isImporting()
-    );
+    private readonly isOverlayImmediate = computed(() => {
+        if (this.xtreamStore.isImporting()) {
+            return true;
+        }
+        if (this.routeState.currentRoute().kind === 'dashboard') {
+            return Boolean(this.refreshPreparation());
+        }
+        const playlistId = this.routeState.currentContext()?.playlistId;
+        return (
+            playlistId !== undefined &&
+            this.isRefreshPreparationRunningForPlaylist(playlistId)
+        );
+    });
     private readonly localLoadDelayElapsed = signal(false);
 
     readonly showXtreamImportOverlay = computed(