fix: stabilize failing test regressions across src and launcher lanes

- Fix log pruning cutoff math using BigInt `mtimeNs` to avoid Bun mtime precision loss
- Fix stats CLI lifetime rebuild timestamp units in tests and log output; add `formatLoggedNumber` guard
- Use `performance.now()` in subtitle sidebar auto-follow to isolate from test time injection
- Harden renderer global cleanup tests with descriptor save/restore instead of assuming globals absent
- Isolate `node:http` fallback in stats-server test with stub and assertion
- Fix AniSkip fallback title: cleaned basename beats generic parent dirs; episode-only filenames still prefer series directory

src/renderer/modals/playlist-browser.test.ts

@@ -302,22 +302,28 @@ function setupPlaylistBrowserModalTest(options?: {
 }
 
 test('playlist browser test cleanup must delete injected globals that were originally absent', () => {
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
-
-  const env = setupPlaylistBrowserModalTest();
-
+  const previousWindowDescriptor = Object.getOwnPropertyDescriptor(globalThis, 'window');
+  const previousDocumentDescriptor = Object.getOwnPropertyDescriptor(globalThis, 'document');
   try {
+    Reflect.deleteProperty(globalThis, 'window');
+    Reflect.deleteProperty(globalThis, 'document');
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
+
+    const env = setupPlaylistBrowserModalTest();
+
     assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), true);
     assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), true);
-  } finally {
     env.restore();
-  }
 
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
-  assert.equal(typeof globalThis.window, 'undefined');
-  assert.equal(typeof globalThis.document, 'undefined');
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
+    assert.equal(typeof globalThis.window, 'undefined');
+    assert.equal(typeof globalThis.document, 'undefined');
+  } finally {
+    restoreGlobalDescriptor('window', previousWindowDescriptor);
+    restoreGlobalDescriptor('document', previousDocumentDescriptor);
+  }
 });
 
 test('playlist browser modal opens with playlist-focused current item selection', async () => {

src/renderer/modals/subtitle-sidebar.test.ts

@@ -74,6 +74,18 @@ function createListStub() {
   };
 }
 
+test.afterEach(() => {
+  if (Object.prototype.hasOwnProperty.call(globalThis, 'window') && globalThis.window === undefined) {
+    Reflect.deleteProperty(globalThis, 'window');
+  }
+  if (
+    Object.prototype.hasOwnProperty.call(globalThis, 'document') &&
+    globalThis.document === undefined
+  ) {
+    Reflect.deleteProperty(globalThis, 'document');
+  }
+});
+
 test('findActiveSubtitleCueIndex prefers timing match before text fallback', () => {
   const cues = [
     { startTime: 1, endTime: 2, text: 'same' },

src/renderer/modals/subtitle-sidebar.ts

@@ -8,6 +8,14 @@ const CLICK_SEEK_OFFSET_SEC = 0.08;
 const SNAPSHOT_POLL_INTERVAL_MS = 80;
 const EMBEDDED_SIDEBAR_MIN_WIDTH_PX = 240;
 const EMBEDDED_SIDEBAR_MAX_RATIO = 0.45;
+
+function nowForUiTiming(): number {
+  if (typeof performance !== 'undefined' && typeof performance.now === 'function') {
+    return performance.now();
+  }
+  return Date.now();
+}
+
 function subtitleCueListsEqual(a: SubtitleCue[], b: SubtitleCue[]): boolean {
   if (a.length !== b.length) {
     return false;
@@ -294,7 +302,7 @@ export function createSubtitleSidebarModal(
       !ctx.state.subtitleSidebarAutoScroll ||
       ctx.state.subtitleSidebarActiveCueIndex < 0 ||
       (!force && ctx.state.subtitleSidebarActiveCueIndex === previousActiveCueIndex) ||
-      Date.now() < ctx.state.subtitleSidebarManualScrollUntilMs
+      nowForUiTiming() < ctx.state.subtitleSidebarManualScrollUntilMs
     ) {
       return;
     }
@@ -547,7 +555,7 @@ export function createSubtitleSidebarModal(
       seekToCue(cue);
     });
     ctx.dom.subtitleSidebarList.addEventListener('wheel', () => {
-      ctx.state.subtitleSidebarManualScrollUntilMs = Date.now() + MANUAL_SCROLL_HOLD_MS;
+      ctx.state.subtitleSidebarManualScrollUntilMs = nowForUiTiming() + MANUAL_SCROLL_HOLD_MS;
     });
     ctx.dom.subtitleSidebarContent.addEventListener('mouseenter', async () => {
       subtitleSidebarHovered = true;

src/renderer/modals/youtube-track-picker.test.ts

@@ -92,6 +92,17 @@ function restoreGlobalProp<K extends keyof typeof globalThis>(
   Reflect.deleteProperty(globalThis, key);
 }
 
+function restoreGlobalDescriptor<K extends keyof typeof globalThis>(
+  key: K,
+  descriptor: PropertyDescriptor | undefined,
+) {
+  if (descriptor) {
+    Object.defineProperty(globalThis, key, descriptor);
+    return;
+  }
+  Reflect.deleteProperty(globalThis, key);
+}
+
 function setupYoutubePickerTestEnv(options?: {
   windowValue?: YoutubePickerTestWindow;
   customEventValue?: unknown;
@@ -153,20 +164,30 @@ function setupYoutubePickerTestEnv(options?: {
 }
 
 test('youtube picker test env restore deletes injected globals that were originally absent', () => {
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
+  const previousWindowDescriptor = Object.getOwnPropertyDescriptor(globalThis, 'window');
+  const previousDocumentDescriptor = Object.getOwnPropertyDescriptor(globalThis, 'document');
 
-  const env = setupYoutubePickerTestEnv();
+  try {
+    Reflect.deleteProperty(globalThis, 'window');
+    Reflect.deleteProperty(globalThis, 'document');
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
 
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), true);
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), true);
+    const env = setupYoutubePickerTestEnv();
 
-  env.restore();
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), true);
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), true);
 
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
-  assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
-  assert.equal(typeof globalThis.window, 'undefined');
-  assert.equal(typeof globalThis.document, 'undefined');
+    env.restore();
+
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'window'), false);
+    assert.equal(Object.prototype.hasOwnProperty.call(globalThis, 'document'), false);
+    assert.equal(typeof globalThis.window, 'undefined');
+    assert.equal(typeof globalThis.document, 'undefined');
+  } finally {
+    restoreGlobalDescriptor('window', previousWindowDescriptor);
+    restoreGlobalDescriptor('document', previousDocumentDescriptor);
+  }
 });
 
 test('youtube track picker close restores focus and mouse-ignore state', () => {