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

backlog/tasks/task-274 - Stabilize-current-failing-test-regressions.md

@@ -0,0 +1,59 @@
+---
+id: TASK-274
+title: Stabilize current failing test regressions
+status: Done
+assignee:
+  - codex
+created_date: '2026-04-04 04:40'
+updated_date: '2026-04-04 05:01'
+labels: []
+dependencies: []
+documentation:
+  - docs/workflow/verification.md
+  - docs/architecture/README.md
+priority: high
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Investigate and fix the current src/test failures across stats CLI lifetime rebuild handling, immersion tracker lifetime rebuild idempotency, renderer test environment cleanup helpers, subtitle sidebar auto-follow behavior, and log retention pruning so the maintained test lanes pass again.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Stats CLI lifetime rebuild behavior passes the current regression coverage.
+- [x] #2 Immersion tracker lifetime rebuild backfill remains idempotent under the existing runtime test.
+- [x] #3 Renderer modal test helpers restore injected globals exactly to prior state.
+- [x] #4 Log pruning removes files older than the configured retention window deterministically.
+- [x] #5 Relevant targeted test files pass after the fixes.
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Reproduce the failing specs in isolation to separate deterministic regressions from suite-order pollution.
+2. Fix source or test-helper logic for the three isolated failures: log retention cutoff, stats CLI lifetime rebuild timestamp handling, and subtitle sidebar initial jump behavior.
+3. Harden renderer modal cleanup regressions so tests verify descriptor restoration without assuming global window/document start absent.
+4. Re-run the targeted failing files, then the required verification gate for the touched areas and record results.
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Targeted regressions fixed in log pruning, stats CLI lifetime logging/tests, subtitle sidebar auto-follow timing, and renderer global cleanup test isolation.
+
+Verification: `bun test src/main/runtime/stats-cli-command.test.ts src/shared/log-files.test.ts src/renderer/modals/playlist-browser.test.ts src/renderer/modals/youtube-track-picker.test.ts src/renderer/modals/subtitle-sidebar.test.ts` passed.
+
+Verification: `bun run test:src` still exits non-zero because of unrelated existing errors in `src/core/services/anilist/anilist-token-store.test.ts` (`Bun.serve is not a function`) plus one remaining non-task failure elsewhere; the originally reported regressions are green in the maintained lane.
+
+User reported `test:full` still failing after the first regression pass. Reopened to clear the remaining `test:src` fail plus the existing unhandled test errors before handoff.
+
+Verified final gate with `bun run test:launcher:unit:src` and `bun run test:full`; both pass after fixing the launcher AniSkip fallback title regression and the earlier src-lane regressions.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Stabilized the failing test regressions across source and launcher lanes. Fixed log pruning cutoff math under Bun BigInt mtimes, subtitle sidebar auto-follow timing, renderer global cleanup test isolation, stats CLI lifetime rebuild logging/tests, stats-server node:http fallback isolation, and launcher AniSkip fallback title resolution so basename titles beat generic parent directories while episode-only filenames still prefer the series directory. Verification passed with `bun test launcher/aniskip-metadata.test.ts`, `bun run test:launcher:unit:src`, and `bun run test:full`.
+<!-- SECTION:FINAL_SUMMARY:END -->

launcher/aniskip-metadata.ts

@@ -125,6 +125,12 @@ function titleOverlapScore(expectedTitle: string, candidateTitle: string): numbe
   if (!expected || !candidate) return 0;
 
   if (candidate.includes(expected)) return 120;
+  if (
+    candidate.split(' ').length >= 2 &&
+    ` ${expected} `.includes(` ${candidate} `)
+  ) {
+    return 90;
+  }
 
   const expectedTokens = tokenizeMatchWords(expectedTitle);
   if (expectedTokens.length === 0) return 0;
@@ -339,6 +345,12 @@ function isSeasonDirectoryName(value: string): boolean {
   return /^(?:season|s)[\s._-]*\d{1,2}$/i.test(value.trim());
 }
 
+function isEpisodeOnlyBaseName(value: string): boolean {
+  return /^(?:[Ss]\d{1,2}[Ee]\d{1,3}|[Ee][Pp]?[\s._-]*\d{1,3}|\d{1,3})(?:$|[\s._-])/.test(
+    value.trim(),
+  );
+}
+
 function inferTitleFromPath(mediaPath: string): string {
   const directory = path.dirname(mediaPath);
   const segments = directory.split(/[\\/]+/).filter((segment) => segment.length > 0);
@@ -445,8 +457,11 @@ export function inferAniSkipMetadataForFile(
   }
 
   const baseName = path.basename(mediaPath, path.extname(mediaPath));
+  const cleanedBaseName = cleanupTitle(baseName);
   const pathTitle = inferTitleFromPath(mediaPath);
-  const fallbackTitle = pathTitle || cleanupTitle(baseName) || baseName;
+  const fallbackTitle = isEpisodeOnlyBaseName(baseName)
+    ? pathTitle || cleanedBaseName || baseName
+    : cleanedBaseName || pathTitle || baseName;
   return {
     title: fallbackTitle,
     season: detectSeasonFromNameOrDir(mediaPath),

src/core/services/__tests__/stats-server.test.ts

@@ -1,6 +1,7 @@
 import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 import fs from 'node:fs';
+import http from 'node:http';
 import os from 'node:os';
 import path from 'node:path';
 import { createStatsApp, startStatsServer } from '../stats-server.js';
@@ -1172,7 +1173,23 @@ describe('stats server API routes', () => {
 
     const bun = globalThis as typeof globalThis & BunRuntime;
     const originalServe = bun.Bun.serve;
+    const originalCreateServer = http.createServer;
+    let listenedWith: { port: number; hostname: string } | null = null;
+    let closeCalls = 0;
     bun.Bun.serve = undefined;
+    (
+      http as typeof http & {
+        createServer: typeof http.createServer;
+      }
+    ).createServer = (() =>
+      ({
+        listen: (port: number, hostname: string) => {
+          listenedWith = { port, hostname };
+        },
+        close: () => {
+          closeCalls += 1;
+        },
+      }) as unknown as ReturnType<typeof http.createServer>) as typeof http.createServer;
 
     try {
       const server = startStatsServer({
@@ -1181,9 +1198,16 @@ describe('stats server API routes', () => {
         tracker: createMockTracker(),
       });
 
+      assert.deepEqual(listenedWith, { port: 0, hostname: '127.0.0.1' });
       server.close();
+      assert.equal(closeCalls, 1);
     } finally {
       bun.Bun.serve = originalServe;
+      (
+        http as typeof http & {
+          createServer: typeof http.createServer;
+        }
+      ).createServer = originalCreateServer;
     }
   });
 });

src/main/runtime/stats-cli-command.test.ts

@@ -236,7 +236,7 @@ test('stats cli command runs lifetime rebuild when cleanup lifetime mode is requ
     getImmersionTracker: () => ({
       rebuildLifetimeSummaries: async () => ({
         appliedSessions: 4,
-        rebuiltAtMs: 1_710_000_000_000,
+        rebuiltAtMs: 1_710_000_000,
       }),
     }),
   });
@@ -252,7 +252,7 @@ test('stats cli command runs lifetime rebuild when cleanup lifetime mode is requ
 
   assert.deepEqual(calls, [
     'ensureImmersionTrackerStarted',
-    'info:Stats lifetime rebuild complete: appliedSessions=4 rebuiltAtMs=1710000000000',
+    'info:Stats lifetime rebuild complete: appliedSessions=4 rebuiltAtMs=1710000000',
   ]);
   assert.deepEqual(responses, [
     {
@@ -285,6 +285,7 @@ async function waitForPendingAnimeMetadata(
 
 test('tracker rebuildLifetimeSummaries backfills retained sessions and is idempotent', async () => {
   const dbPath = makeDbPath();
+  const previousNowMs = globalThis.__subminerTestNowMs;
   let tracker:
     | import('../../core/services/immersion-tracker-service').ImmersionTrackerService
     | null = null;
@@ -298,19 +299,23 @@ test('tracker rebuildLifetimeSummaries backfills retained sessions and is idempo
   const { Database } = await import('../../core/services/immersion-tracker/sqlite');
 
   try {
+    globalThis.__subminerTestNowMs = 1_700_000_000;
     tracker = new ImmersionTrackerService({ dbPath });
     tracker.handleMediaChange('/tmp/Frieren S01E01.mkv', 'Episode 1');
     await waitForPendingAnimeMetadata(tracker);
     tracker.recordCardsMined(2);
     tracker.recordSubtitleLine('first line', 0, 1);
+    globalThis.__subminerTestNowMs = 1_700_001_000;
     tracker.destroy();
     tracker = null;
 
+    globalThis.__subminerTestNowMs = 1_700_002_000;
     tracker2 = new ImmersionTrackerService({ dbPath });
     tracker2.handleMediaChange('/tmp/Frieren S01E02.mkv', 'Episode 2');
     await waitForPendingAnimeMetadata(tracker2);
     tracker2.recordCardsMined(1);
     tracker2.recordSubtitleLine('second line', 0, 1);
+    globalThis.__subminerTestNowMs = 1_700_003_000;
     tracker2.destroy();
     tracker2 = null;
 
@@ -357,8 +362,10 @@ test('tracker rebuildLifetimeSummaries backfills retained sessions and is idempo
     `);
     beforeDb.close();
 
+    globalThis.__subminerTestNowMs = 1_700_004_000;
     tracker3 = new ImmersionTrackerService({ dbPath });
     const firstRebuild = await tracker3.rebuildLifetimeSummaries();
+    globalThis.__subminerTestNowMs = 1_700_005_000;
     const secondRebuild = await tracker3.rebuildLifetimeSummaries();
 
     const rebuiltDb = new Database(dbPath);
@@ -405,6 +412,7 @@ test('tracker rebuildLifetimeSummaries backfills retained sessions and is idempo
     assert.equal(secondRebuild.appliedSessions, firstRebuild.appliedSessions);
     assert.ok(secondRebuild.rebuiltAtMs >= firstRebuild.rebuiltAtMs);
   } finally {
+    globalThis.__subminerTestNowMs = previousNowMs;
     tracker?.destroy();
     tracker2?.destroy();
     tracker3?.destroy();
@@ -417,7 +425,7 @@ test('stats cli command runs lifetime rebuild when requested', async () => {
     getImmersionTracker: () => ({
       rebuildLifetimeSummaries: async () => ({
         appliedSessions: 4,
-        rebuiltAtMs: 1_710_000_000_000,
+        rebuiltAtMs: 1_710_000_000,
       }),
     }),
   });
@@ -433,7 +441,7 @@ test('stats cli command runs lifetime rebuild when requested', async () => {
 
   assert.deepEqual(calls, [
     'ensureImmersionTrackerStarted',
-    'info:Stats lifetime rebuild complete: appliedSessions=4 rebuiltAtMs=1710000000000',
+    'info:Stats lifetime rebuild complete: appliedSessions=4 rebuiltAtMs=1710000000',
   ]);
   assert.deepEqual(responses, [
     {

src/main/runtime/stats-cli-command.ts

@@ -32,6 +32,10 @@ type BackgroundStatsStopResult = {
   stale: boolean;
 };
 
+function formatLoggedNumber(value: number): string {
+  return Number.isFinite(value) ? value.toString() : String(value);
+}
+
 export function writeStatsCliCommandResponse(
   responsePath: string,
   payload: StatsCliCommandResponse,
@@ -143,7 +147,7 @@ export function createRunStatsCliCommandHandler(deps: {
         }
         const result = await tracker.rebuildLifetimeSummaries();
         deps.logInfo(
-          `Stats lifetime rebuild complete: appliedSessions=${result.appliedSessions} rebuiltAtMs=${result.rebuiltAtMs}`,
+          `Stats lifetime rebuild complete: appliedSessions=${formatLoggedNumber(result.appliedSessions)} rebuiltAtMs=${formatLoggedNumber(result.rebuiltAtMs)}`,
         );
         writeResponseSafe(args.statsResponsePath, { ok: true });
         return;

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', () => {
+  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();
 
-  try {
     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');
+  } 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;
@@ -153,6 +164,12 @@ function setupYoutubePickerTestEnv(options?: {
 }
 
 test('youtube picker test env restore deletes injected globals that were originally absent', () => {
+  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);
 
@@ -167,6 +184,10 @@ test('youtube picker test env restore deletes injected globals that were origina
     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', () => {

src/shared/log-files.ts

@@ -9,6 +9,36 @@ export const DEFAULT_LOG_MAX_BYTES = 10 * 1024 * 1024;
 
 const TRUNCATED_MARKER = '[truncated older log content]\n';
 const prunedDirectories = new Set<string>();
+const NS_PER_MS = 1_000_000n;
+const MS_PER_DAY = 86_400_000n;
+
+function floorDiv(left: number, right: number): number {
+  return Math.floor(left / right);
+}
+
+function daysFromCivil(year: number, month: number, day: number): bigint {
+  const adjustedYear = year - (month <= 2 ? 1 : 0);
+  const era = floorDiv(adjustedYear >= 0 ? adjustedYear : adjustedYear - 399, 400);
+  const yearOfEra = adjustedYear - era * 400;
+  const monthIndex = month + (month > 2 ? -3 : 9);
+  const dayOfYear = floorDiv(153 * monthIndex + 2, 5) + day - 1;
+  const dayOfEra =
+    yearOfEra * 365 + floorDiv(yearOfEra, 4) - floorDiv(yearOfEra, 100) + dayOfYear;
+  return BigInt(era * 146097 + dayOfEra - 719468);
+}
+
+function dateToEpochMs(date: Date): bigint {
+  const dayCount = daysFromCivil(
+    date.getUTCFullYear(),
+    date.getUTCMonth() + 1,
+    date.getUTCDate(),
+  );
+  const timeOfDayMs = BigInt(
+    ((date.getUTCHours() * 60 + date.getUTCMinutes()) * 60 + date.getUTCSeconds()) * 1000 +
+      date.getUTCMilliseconds(),
+  );
+  return dayCount * MS_PER_DAY + timeOfDayMs;
+}
 
 export function resolveLogBaseDir(options?: {
   platform?: NodeJS.Platform;
@@ -52,16 +82,20 @@ export function pruneLogFiles(
     return;
   }
 
-  const cutoffMs = (options?.now ?? new Date()).getTime() - retentionDays * 24 * 60 * 60 * 1000;
+  const cutoffDate = new Date(options?.now ?? new Date());
+  cutoffDate.setUTCDate(cutoffDate.getUTCDate() - retentionDays);
+  const cutoffNs = dateToEpochMs(cutoffDate) * NS_PER_MS;
   for (const entry of entries) {
     const candidate = path.join(logsDir, entry);
-    let stats: fs.Stats;
+    let stats: fs.BigIntStats;
     try {
-      stats = fs.statSync(candidate);
+      stats = fs.statSync(candidate, { bigint: true });
     } catch {
       continue;
     }
-    if (!stats.isFile() || !entry.endsWith('.log') || stats.mtimeMs >= cutoffMs) continue;
+    if (!stats.isFile() || !entry.endsWith('.log') || stats.mtimeNs >= cutoffNs) {
+      continue;
+    }
     try {
       fs.rmSync(candidate, { force: true });
     } catch {