fix(notification): replace repeated desktop status toasts

- Add optional replaceId to showDesktopNotification; a repeated id closes the prior toast instead of stacking a new one
- Character dictionary auto-sync now shares one replaceId across checking/generating/importing/ready phases
- Startup OSD sequencer passes its lane id as replaceId so each startup lane keeps a single live notification

changes/character-dictionary-large-imports.md

@@ -0,0 +1,7 @@
+type: fixed
+area: character dictionary
+
+- A large character dictionary no longer fails to install. The Yomitan import (and the delete that precedes it) used a flat 7 second budget, so a series like One Piece failed with `importYomitanDictionary(merged.zip) timed out after 7000ms` while the import was still healthy. The budget is now sized from the merged ZIP (2 minutes plus 6 seconds per MB, capped at 30 minutes); the quick queries keep the 7 second budget.
+- The "Generating character dictionary" notification now reports what it is doing instead of one static message for the whole run: the AniList page and character count while characters download (`page 12, 587 characters`), then `image 240/1220, ~4m left` per downloaded character/voice actor image, then `name 800/1220` for MeCab name splits and `saving snapshot` at the end. Updates are throttled to one per second, and every stage change and final item always reports.
+- Every long phase also carries an elapsed clock (`· 1m 35s`), refreshed every 5 seconds even when nothing else moves, so a stalled step is visibly different from a frozen app. Long imports tick the same way.
+- Image downloads are also logged every 100 files, and the import logs the timeout it computed.

src/core/utils/notification.ts

@@ -52,9 +52,15 @@ function resolveRuntimeDefaultNotificationIconPath(): string | null {
   });
 }
 
+/**
+ * Live notifications keyed by `replaceId`. Electron exposes no native "replace this notification"
+ * flag, so a repeated status closes its predecessor instead of stacking a fresh toast per update.
+ */
+const notificationsByReplaceId = new Map<string, Electron.Notification>();
+
 export function showDesktopNotification(
   title: string,
-  options: { body?: string; icon?: string },
+  options: { body?: string; icon?: string; replaceId?: string },
 ): void {
   const notificationOptions: {
     title: string;
@@ -98,5 +104,15 @@ export function showDesktopNotification(
   }
 
   const notification = new Notification(notificationOptions);
+  const replaceId = options.replaceId?.trim();
+  if (replaceId) {
+    notificationsByReplaceId.get(replaceId)?.close();
+    notificationsByReplaceId.set(replaceId, notification);
+    notification.once('close', () => {
+      if (notificationsByReplaceId.get(replaceId) === notification) {
+        notificationsByReplaceId.delete(replaceId);
+      }
+    });
+  }
   notification.show();
 }

src/main/character-dictionary-runtime.test.ts

@@ -1903,7 +1903,7 @@ test('generateForCurrentMedia logs progress while resolving and rebuilding snaps
       '[dictionary] current anime guess: The Eminence in Shadow (episode 5)',
       '[dictionary] AniList match: The Eminence in Shadow -> AniList 130298',
       '[dictionary] snapshot miss for AniList 130298, fetching characters',
-      '[dictionary] downloaded AniList character page 1 for AniList 130298',
+      '[dictionary] downloaded AniList character page 1 for AniList 130298 (1 characters)',
       '[dictionary] downloading 1 images for AniList 130298',
       '[dictionary] stored snapshot for AniList 130298: 16 terms',
       '[dictionary] building ZIP for AniList 130298',

src/main/character-dictionary-runtime.ts

@@ -64,6 +64,7 @@ export type {
   CharacterDictionarySnapshotProgress,
   CharacterDictionarySnapshotProgressCallbacks,
   CharacterDictionarySnapshotResult,
+  CharacterDictionarySnapshotStageProgress,
   MergedCharacterDictionaryBuildResult,
 } from './character-dictionary-runtime/types';
 
@@ -363,19 +364,28 @@ export function createCharacterDictionaryRuntimeService(deps: CharacterDictionar
       deps.logInfo?.(`[dictionary] snapshot stale for AniList ${mediaId}: ${refreshReason}`);
     }
 
+    const progressMediaTitle = mediaTitleHint || `AniList ${mediaId}`;
     progress?.onGenerating?.({
       mediaId,
-      mediaTitle: mediaTitleHint || `AniList ${mediaId}`,
+      mediaTitle: progressMediaTitle,
     });
     deps.logInfo?.(`[dictionary] snapshot miss for AniList ${mediaId}, fetching characters`);
 
     const { mediaTitle: fetchedMediaTitle, characters } = await fetchCharactersForMedia(
       mediaId,
       beforeRequest,
-      (page) => {
+      (page, charactersSoFar) => {
         deps.logInfo?.(
-          `[dictionary] downloaded AniList character page ${page} for AniList ${mediaId}`,
+          `[dictionary] downloaded AniList character page ${page} for AniList ${mediaId} (${charactersSoFar} characters)`,
         );
+        progress?.onGenerateProgress?.({
+          mediaId,
+          mediaTitle: progressMediaTitle,
+          stage: 'characters',
+          completed: charactersSoFar,
+          total: null,
+          page,
+        });
       },
     );
     if (characters.length === 0) {
@@ -403,12 +413,26 @@ export function createCharacterDictionaryRuntimeService(deps: CharacterDictionar
       );
     }
     let hasAttemptedImageDownload = false;
+    let attemptedImageCount = 0;
     for (const entry of allImageUrls) {
       if (hasAttemptedImageDownload) {
         await sleepMs(CHARACTER_IMAGE_DOWNLOAD_DELAY_MS);
       }
       hasAttemptedImageDownload = true;
       const image = await downloadCharacterImage(entry.url, entry.id);
+      attemptedImageCount += 1;
+      progress?.onGenerateProgress?.({
+        mediaId,
+        mediaTitle: progressMediaTitle,
+        stage: 'images',
+        completed: attemptedImageCount,
+        total: allImageUrls.length,
+      });
+      if (attemptedImageCount % 100 === 0) {
+        deps.logInfo?.(
+          `[dictionary] downloaded ${attemptedImageCount}/${allImageUrls.length} images for AniList ${mediaId}`,
+        );
+      }
       if (!image) continue;
       if (entry.kind === 'character') {
         imagesByCharacterId.set(entry.id, {
@@ -425,11 +449,31 @@ export function createCharacterDictionaryRuntimeService(deps: CharacterDictionar
 
     const nameSplitTokenizerAvailable = isNameSplitTokenizerAvailable();
     const resolvedNameSplits = nameSplitTokenizerAvailable
-      ? await resolveJapaneseNameSplits(characters, deps.tokenizeJapaneseName!, deps.logWarn)
+      ? await resolveJapaneseNameSplits(
+          characters,
+          deps.tokenizeJapaneseName!,
+          deps.logWarn,
+          (completed, total) => {
+            progress?.onGenerateProgress?.({
+              mediaId,
+              mediaTitle: progressMediaTitle,
+              stage: 'names',
+              completed,
+              total,
+            });
+          },
+        )
       : undefined;
     const nameSplitSource =
       resolvedNameSplits && resolvedNameSplits.size > 0 ? 'mecab' : 'heuristic';
 
+    progress?.onGenerateProgress?.({
+      mediaId,
+      mediaTitle: progressMediaTitle,
+      stage: 'saving',
+      completed: 0,
+      total: null,
+    });
     const snapshot = buildSnapshotFromCharacters(
       mediaId,
       fetchedMediaTitle || mediaTitleHint || `AniList ${mediaId}`,

src/main/character-dictionary-runtime/fetch.ts

@@ -278,7 +278,7 @@ export async function fetchAniListMediaCandidateById(
 export async function fetchCharactersForMedia(
   mediaId: number,
   beforeRequest?: () => Promise<void>,
-  onPageFetched?: (page: number) => void,
+  onPageFetched?: (page: number, charactersSoFar: number) => void,
 ): Promise<{
   mediaTitle: string;
   characters: CharacterRecord[];
@@ -345,7 +345,6 @@ export async function fetchCharactersForMedia(
       },
       beforeRequest,
     );
-    onPageFetched?.(page);
 
     const media = data.Media;
     if (!media) {
@@ -415,6 +414,8 @@ export async function fetchCharactersForMedia(
       });
     }
 
+    onPageFetched?.(page, characters.length);
+
     const hasNextPage = Boolean(media.characters?.pageInfo?.hasNextPage);
     if (!hasNextPage) {
       break;

src/main/character-dictionary-runtime/name-split-resolver.ts

@@ -86,8 +86,10 @@ export async function resolveJapaneseNameSplits(
   characters: CharacterRecord[],
   tokenize: NameSplitTokenizer,
   logWarn?: (message: string) => void,
+  onCharacterResolved?: (completed: number, total: number) => void,
 ): Promise<Map<string, ResolvedNameSplit>> {
   const splits = new Map<string, ResolvedNameSplit>();
+  let resolvedCharacters = 0;
   for (const character of characters) {
     const familyHintReading = buildReadingFromHint(character.lastNameHint?.trim() || '');
     const givenHintReading = buildReadingFromHint(character.firstNameHint?.trim() || '');
@@ -113,6 +115,8 @@ export async function resolveJapaneseNameSplits(
         splits.set(name, { family, given });
       }
     }
+    resolvedCharacters += 1;
+    onCharacterResolved?.(resolvedCharacters, characters.length);
   }
   return splits;
 }

src/main/character-dictionary-runtime/types.ts

@@ -122,9 +122,24 @@ export type CharacterDictionarySnapshotProgress = {
   mediaTitle: string;
 };
 
+export type CharacterDictionarySnapshotStage = 'characters' | 'images' | 'names' | 'saving';
+
+/**
+ * Fine-grained generation progress. `total` is null while the work size is still unknown (AniList
+ * paginates characters, so the character count only settles on the last page).
+ */
+export type CharacterDictionarySnapshotStageProgress = CharacterDictionarySnapshotProgress & {
+  stage: CharacterDictionarySnapshotStage;
+  completed: number;
+  total: number | null;
+  /** AniList page currently being downloaded; only set during the `characters` stage. */
+  page?: number;
+};
+
 export type CharacterDictionarySnapshotProgressCallbacks = {
   onChecking?: (progress: CharacterDictionarySnapshotProgress) => void;
   onGenerating?: (progress: CharacterDictionarySnapshotProgress) => void;
+  onGenerateProgress?: (progress: CharacterDictionarySnapshotStageProgress) => void;
 };
 
 export type MergedCharacterDictionaryBuildResult = {

src/main/character-dictionary-runtime/zip.test.ts

@@ -3,7 +3,7 @@ import fs from 'node:fs';
 import os from 'node:os';
 import path from 'node:path';
 import test from 'node:test';
-import { buildDictionaryZip } from './zip';
+import { buildDictionaryZip, readDictionaryZipRevision } from './zip';
 import type { CharacterDictionaryTermEntry } from './types';
 
 function makeTempDir(): string {
@@ -105,3 +105,63 @@ test('buildDictionaryZip writes a valid stored zip without fs.writeFileSync', ()
     cleanupDir(tempDir);
   }
 });
+
+test('readDictionaryZipRevision reads the built revision and rejects foreign archives', () => {
+  const dir = makeTempDir();
+  try {
+    const zipPath = path.join(dir, 'merged.zip');
+    buildDictionaryZip(
+      zipPath,
+      'SubMiner Character Dictionary',
+      'Character names',
+      'rev-42',
+      [
+        {
+          term: 'ルフィ',
+          reading: 'ルフィ',
+          role: 'main',
+          glossary: [],
+        } as unknown as CharacterDictionaryTermEntry,
+      ],
+      [],
+    );
+
+    assert.equal(readDictionaryZipRevision(zipPath), 'rev-42');
+    assert.equal(readDictionaryZipRevision(path.join(dir, 'missing.zip')), null);
+
+    const archive = fs.readFileSync(zipPath);
+    const truncatedPath = path.join(dir, 'truncated.zip');
+    fs.writeFileSync(truncatedPath, archive.subarray(0, 40));
+    assert.equal(readDictionaryZipRevision(truncatedPath), null);
+
+    // An archive cut short after index.json still holds a readable revision, but importing it
+    // would hand Yomitan a half-written file: the missing end-of-central-directory record has to
+    // reject it. One byte off the end is enough to make the record incomplete.
+    for (const missingBytes of [1, 22, archive.length - 200]) {
+      const cutPath = path.join(dir, `cut-${missingBytes}.zip`);
+      fs.writeFileSync(cutPath, archive.subarray(0, archive.length - missingBytes));
+      assert.equal(readDictionaryZipRevision(cutPath), null, `cut of ${missingBytes} bytes`);
+    }
+
+    // Same size, corrupt directory: a record overwritten in place has to be rejected too.
+    const centralStart = archive.readUInt32LE(archive.length - 22 + 16);
+    const brokenSignaturePath = path.join(dir, 'broken-signature.zip');
+    const brokenSignature = Buffer.from(archive);
+    brokenSignature.writeUInt32LE(0xdeadbeef, centralStart);
+    fs.writeFileSync(brokenSignaturePath, brokenSignature);
+    assert.equal(readDictionaryZipRevision(brokenSignaturePath), null);
+
+    const brokenLengthPath = path.join(dir, 'broken-length.zip');
+    const brokenLength = Buffer.from(archive);
+    // Name length that runs the walk past the end of the directory.
+    brokenLength.writeUInt16LE(0xffff, centralStart + 28);
+    fs.writeFileSync(brokenLengthPath, brokenLength);
+    assert.equal(readDictionaryZipRevision(brokenLengthPath), null);
+
+    const foreignPath = path.join(dir, 'foreign.zip');
+    fs.writeFileSync(foreignPath, Buffer.from('not a zip at all', 'utf8'));
+    assert.equal(readDictionaryZipRevision(foreignPath), null);
+  } finally {
+    cleanupDir(dir);
+  }
+});

src/main/character-dictionary-runtime/zip.ts

@@ -1,5 +1,5 @@
 import * as path from 'path';
-import { writeStoredZip } from '../../shared/stored-zip';
+import { readStoredZipFirstFile, writeStoredZip } from '../../shared/stored-zip';
 import { ensureDir } from './fs-utils';
 import type { CharacterDictionarySnapshotImage, CharacterDictionaryTermEntry } from './types';
 
@@ -31,6 +31,23 @@ function createTagBank(): Array<[string, string, number, string, number]> {
   ];
 }
 
+/**
+ * Revision recorded inside a built dictionary ZIP, or null when the archive is missing, truncated,
+ * or not one of ours. `index.json` is always the first entry written by {@link buildDictionaryZip}.
+ */
+export function readDictionaryZipRevision(zipPath: string): string | null {
+  const firstFile = readStoredZipFirstFile(zipPath);
+  if (!firstFile || firstFile.name !== 'index.json') {
+    return null;
+  }
+  try {
+    const index = JSON.parse(firstFile.data.toString('utf8')) as { revision?: unknown };
+    return typeof index.revision === 'string' && index.revision.length > 0 ? index.revision : null;
+  } catch {
+    return null;
+  }
+}
+
 export function buildDictionaryZip(
   outputPath: string,
   dictionaryTitle: string,

src/main/runtime/character-dictionary-auto-sync-messages.ts

@@ -0,0 +1,90 @@
+import type { CharacterDictionarySnapshotStageProgress } from '../character-dictionary-runtime';
+
+export function buildSyncingMessage(mediaTitle: string): string {
+  return `Updating character dictionary for ${mediaTitle}...`;
+}
+
+export function buildCheckingMessage(mediaTitle: string): string {
+  return `Checking character dictionary for ${mediaTitle}...`;
+}
+
+export function buildGeneratingMessage(mediaTitle: string, detail?: string): string {
+  return detail
+    ? `Generating character dictionary for ${mediaTitle} (${detail})...`
+    : `Generating character dictionary for ${mediaTitle}...`;
+}
+
+export function formatCharacterDictionaryProgressDetail(
+  progress: CharacterDictionarySnapshotStageProgress,
+  remainingMs: number | null,
+): string {
+  if (progress.stage === 'saving') {
+    return 'saving snapshot';
+  }
+  if (progress.stage === 'names') {
+    return progress.total !== null && progress.total > 0
+      ? `name ${progress.completed}/${progress.total}`
+      : `${progress.completed} names`;
+  }
+  if (progress.stage === 'images') {
+    const counted =
+      progress.total !== null && progress.total > 0
+        ? `image ${progress.completed}/${progress.total}`
+        : `${progress.completed} images`;
+    return remainingMs !== null
+      ? `${counted}, ~${formatRemainingDuration(remainingMs)} left`
+      : counted;
+  }
+  const page = typeof progress.page === 'number' ? `page ${progress.page}, ` : '';
+  return `${page}${progress.completed} characters`;
+}
+
+export function formatElapsedDuration(elapsedMs: number): string {
+  const totalSeconds = Math.max(0, Math.floor(elapsedMs / 1000));
+  const minutes = Math.floor(totalSeconds / 60);
+  const seconds = totalSeconds % 60;
+  return minutes > 0 ? `${minutes}m ${String(seconds).padStart(2, '0')}s` : `${seconds}s`;
+}
+
+/** Coarser than the elapsed clock: an estimate that ticks every second reads as precision it lacks. */
+export function formatRemainingDuration(remainingMs: number): string {
+  const totalSeconds = Math.max(1, Math.round(remainingMs / 1000));
+  if (totalSeconds >= 60) {
+    return `${Math.max(1, Math.round(totalSeconds / 60))}m`;
+  }
+  return `${Math.max(5, Math.ceil(totalSeconds / 5) * 5)}s`;
+}
+
+/**
+ * The elapsed clock is the part that proves the app is alive: a stalled network fetch freezes the
+ * counts, but the clock keeps moving.
+ */
+export function joinGeneratingDetail(detail: string | null, elapsedMs: number): string | undefined {
+  const parts = [detail, elapsedMs >= 5_000 ? formatElapsedDuration(elapsedMs) : null].filter(
+    (part): part is string => typeof part === 'string' && part.length > 0,
+  );
+  return parts.length > 0 ? parts.join(' · ') : undefined;
+}
+
+export function buildImportingMessage(mediaTitle: string, elapsedMs?: number): string {
+  const elapsed =
+    typeof elapsedMs === 'number' && elapsedMs >= 1000
+      ? ` (${formatElapsedDuration(elapsedMs)})`
+      : '';
+  return `Importing character dictionary for ${mediaTitle}${elapsed}...`;
+}
+
+export function buildBuildingMessage(mediaTitle: string): string {
+  return `Building character dictionary for ${mediaTitle}...`;
+}
+
+export function buildReadyMessage(mediaTitle: string): string {
+  return `Character dictionary ready for ${mediaTitle}`;
+}
+
+export function buildFailedMessage(mediaTitle: string | null, errorMessage: string): string {
+  if (mediaTitle) {
+    return `Character dictionary sync failed for ${mediaTitle}: ${errorMessage}`;
+  }
+  return `Character dictionary sync failed: ${errorMessage}`;
+}

src/main/runtime/character-dictionary-auto-sync-notifications.test.ts

@@ -214,3 +214,69 @@ test('auto sync notifications let startup sequencer own osd-system desktop deliv
 
   assert.deepEqual(calls, ['osd:importing', 'desktop:SubMiner:importing']);
 });
+
+test('auto sync desktop notifications reuse one replace id across every phase', () => {
+  const replaceIds: Array<string | undefined> = [];
+  const deps = {
+    getNotificationType: () => 'system' as const,
+    showOsd: () => undefined,
+    showDesktopNotification: (_title: string, options: { body?: string; replaceId?: string }) => {
+      replaceIds.push(options.replaceId);
+    },
+  };
+
+  for (const phase of ['checking', 'generating', 'importing', 'ready'] as const) {
+    notifyCharacterDictionaryAutoSyncStatus(makeEvent(phase, phase), deps);
+  }
+
+  assert.deepEqual(replaceIds, [
+    'character-dictionary-auto-sync',
+    'character-dictionary-auto-sync',
+    'character-dictionary-auto-sync',
+    'character-dictionary-auto-sync',
+  ]);
+});
+
+test('overlay-unavailable desktop fallback shares the same replace id', () => {
+  const replaceIds: Array<string | undefined> = [];
+
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('generating', 'generating'), {
+    getNotificationType: () => 'overlay',
+    showOsd: () => undefined,
+    showDesktopNotification: (_title, options) => {
+      replaceIds.push(options.replaceId);
+    },
+  });
+
+  assert.deepEqual(replaceIds, ['character-dictionary-auto-sync']);
+});
+
+test('startup lanes keep one desktop notification per lane', () => {
+  const calls: Array<{ body?: string; replaceId?: string }> = [];
+  const sequencer = createStartupOsdSequencer({
+    getNotificationType: () => 'system',
+    showOsd: () => undefined,
+    showDesktopNotification: (_title, options) => {
+      calls.push(options);
+    },
+  });
+
+  sequencer.markTokenizationReady();
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('generating', 'generating one'), {
+    getNotificationType: () => 'osd',
+    showOsd: () => undefined,
+    showDesktopNotification: () => undefined,
+    startupOsdSequencer: sequencer,
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('generating', 'generating two'), {
+    getNotificationType: () => 'osd',
+    showOsd: () => undefined,
+    showDesktopNotification: () => undefined,
+    startupOsdSequencer: sequencer,
+  });
+
+  assert.deepEqual(
+    calls.map((call) => call.replaceId),
+    ['startup-status', 'startup-status'],
+  );
+});

src/main/runtime/character-dictionary-auto-sync-notifications.ts

@@ -9,7 +9,7 @@ export interface CharacterDictionaryAutoSyncNotificationDeps {
   getNotificationType: () => NotificationType | undefined;
   showOsd: (message: string) => boolean | void;
   showOverlayNotification?: (payload: OverlayNotificationPayload) => void;
-  showDesktopNotification: (title: string, options: { body?: string }) => void;
+  showDesktopNotification: (title: string, options: { body?: string; replaceId?: string }) => void;
   startupOsdSequencer?: {
     notifyCharacterDictionaryStatus: (
       event: StartupOsdSequencerCharacterDictionaryEvent,
@@ -17,6 +17,10 @@ export interface CharacterDictionaryAutoSyncNotificationDeps {
   };
 }
 
+// One live desktop notification for the whole sync: progress updates replace each other and the
+// terminal ready/failed message replaces the last progress one, matching the overlay toast.
+const CHARACTER_DICTIONARY_DESKTOP_NOTIFICATION_ID = 'character-dictionary-auto-sync';
+
 function isTerminalPhase(phase: CharacterDictionaryAutoSyncNotificationEvent['phase']): boolean {
   return phase === 'ready' || phase === 'failed';
 }
@@ -53,7 +57,10 @@ export function notifyCharacterDictionaryAutoSyncStatus(
         persistent: !isTerminalPhase(event.phase),
       });
     } else if (!shouldShowDesktop(type)) {
-      deps.showDesktopNotification('SubMiner', { body: event.message });
+      deps.showDesktopNotification('SubMiner', {
+        body: event.message,
+        replaceId: CHARACTER_DICTIONARY_DESKTOP_NOTIFICATION_ID,
+      });
     }
   }
 
@@ -69,6 +76,9 @@ export function notifyCharacterDictionaryAutoSyncStatus(
   }
 
   if (shouldShowDesktop(type) && !startupSequencerShown) {
-    deps.showDesktopNotification('SubMiner', { body: event.message });
+    deps.showDesktopNotification('SubMiner', {
+      body: event.message,
+      replaceId: CHARACTER_DICTIONARY_DESKTOP_NOTIFICATION_ID,
+    });
   }
 }

src/main/runtime/character-dictionary-auto-sync.test.ts

@@ -3,6 +3,7 @@ import * as fs from 'fs';
 import * as os from 'os';
 import * as path from 'path';
 import test from 'node:test';
+import { buildDictionaryZip } from '../character-dictionary-runtime/zip';
 import {
   createCharacterDictionaryAutoSyncRuntimeService,
   getCharacterDictionaryManagerSnapshot,
@@ -14,6 +15,14 @@ function makeTempDir(): string {
   return fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-char-dict-auto-sync-'));
 }
 
+async function waitUntil(predicate: () => boolean, label: string): Promise<void> {
+  for (let attempt = 0; attempt < 500; attempt += 1) {
+    if (predicate()) return;
+    await new Promise((resolve) => setTimeout(resolve, 0));
+  }
+  throw new Error(`Timed out waiting for ${label}`);
+}
+
 function createDeferred<T>(): { promise: Promise<T>; resolve: (value: T) => void } {
   let resolve!: (value: T) => void;
   const promise = new Promise<T>((nextResolve) => {
@@ -187,7 +196,7 @@ test('auto sync imports merged dictionary and persists MRU state', async () => {
     '[dictionary:auto-sync] syncing current anime snapshot',
     '[dictionary:auto-sync] active AniList media set: 130298 - The Eminence in Shadow',
     '[dictionary:auto-sync] rebuilding merged dictionary for active anime set',
-    '[dictionary:auto-sync] importing merged dictionary: /tmp/subminer-character-dictionary.zip',
+    '[dictionary:auto-sync] importing merged dictionary: /tmp/subminer-character-dictionary.zip (timeout 120000ms)',
     '[dictionary:auto-sync] applying Yomitan settings for SubMiner Character Dictionary',
     '[dictionary:auto-sync] synced AniList 130298: SubMiner Character Dictionary (2544 entries)',
   ]);
@@ -367,7 +376,14 @@ test('auto sync reimports existing merged zip without rebuilding on unchanged re
   const userDataPath = makeTempDir();
   const dictionariesDir = path.join(userDataPath, 'character-dictionaries');
   fs.mkdirSync(dictionariesDir, { recursive: true });
-  fs.writeFileSync(path.join(dictionariesDir, 'merged.zip'), 'cached-zip', 'utf8');
+  buildDictionaryZip(
+    path.join(dictionariesDir, 'merged.zip'),
+    'SubMiner Character Dictionary',
+    'Character names',
+    'rev-7',
+    [{ term: 'フリーレン', reading: 'フリーレン', role: 'main', glossary: [] } as never],
+    [],
+  );
   const mergedBuilds: number[][] = [];
   const imports: string[] = [];
   let importedRevision: string | null = null;
@@ -958,11 +974,9 @@ test('auto sync emits building while merged dictionary generation is in flight',
   });
 
   const syncPromise = runtime.runSyncNow();
-  await Promise.resolve();
-
-  assert.equal(
-    events.some((event) => event.phase === 'building'),
-    true,
+  await waitUntil(
+    () => events.some((event) => event.phase === 'building'),
+    'the building status event',
   );
 
   buildDeferred.resolve({
@@ -1029,8 +1043,7 @@ test('auto sync waits for tokenization-ready gate before Yomitan mutations', asy
   });
 
   const syncPromise = runtime.runSyncNow();
-  await Promise.resolve();
-  await Promise.resolve();
+  await waitUntil(() => calls.includes('wait'), 'the tokenization-ready gate');
 
   assert.deepEqual(calls, ['build', 'wait']);
 
@@ -1039,3 +1052,395 @@ test('auto sync waits for tokenization-ready gate before Yomitan mutations', asy
 
   assert.deepEqual(calls, ['build', 'wait', 'info', 'import', 'settings']);
 });
+
+test('auto sync scales the import timeout with the merged dictionary size', async () => {
+  const userDataPath = makeTempDir();
+  const dictionariesDir = path.join(userDataPath, 'character-dictionaries');
+  fs.mkdirSync(dictionariesDir, { recursive: true });
+  const zipPath = path.join(dictionariesDir, 'merged.zip');
+  // 2 MB of merged dictionary buys ~12s of import budget on top of the base.
+  fs.writeFileSync(zipPath, Buffer.alloc(2 * 1024 * 1024));
+  const events: Array<{ phase: string; message: string }> = [];
+  let importedRevision: string | null = null;
+
+  const runtime = createCharacterDictionaryAutoSyncRuntimeService({
+    userDataPath,
+    getConfig: () => ({ enabled: true, maxLoaded: 3, profileScope: 'all' }),
+    getOrCreateCurrentSnapshot: async () => ({
+      mediaId: 21,
+      mediaTitle: 'ONE PIECE',
+      entryCount: 4000,
+      fromCache: false,
+      updatedAt: 1000,
+    }),
+    buildMergedDictionary: async () => ({
+      zipPath,
+      revision: 'rev-21',
+      dictionaryTitle: 'SubMiner Character Dictionary',
+      entryCount: 4000,
+    }),
+    getYomitanDictionaryInfo: async () =>
+      importedRevision
+        ? [{ title: 'SubMiner Character Dictionary', revision: importedRevision }]
+        : [],
+    importYomitanDictionary: async () => {
+      // Far longer than the quick-operation budget, well inside the size-scaled one.
+      await new Promise((resolve) => setTimeout(resolve, 400));
+      importedRevision = 'rev-21';
+      return true;
+    },
+    deleteYomitanDictionary: async () => true,
+    upsertYomitanDictionarySettings: async () => true,
+    now: () => 1000,
+    // Comfortable for the stubs that resolve immediately, still far under the import's 400ms.
+    operationTimeoutMs: 100,
+    dictionaryImportTimeoutBaseMs: 20,
+    onSyncStatus: (event) => {
+      events.push({ phase: event.phase, message: event.message });
+    },
+  });
+
+  await runtime.runSyncNow();
+
+  assert.equal(
+    events.some((event) => event.phase === 'failed'),
+    false,
+  );
+  assert.deepEqual(events.at(-1), {
+    phase: 'ready',
+    message: 'Character dictionary ready for ONE PIECE',
+  });
+});
+
+test('auto sync reports the scaled budget when an import really does hang', async () => {
+  const userDataPath = makeTempDir();
+  const events: Array<{ phase: string; message: string }> = [];
+
+  const runtime = createCharacterDictionaryAutoSyncRuntimeService({
+    userDataPath,
+    getConfig: () => ({ enabled: true, maxLoaded: 3, profileScope: 'all' }),
+    getOrCreateCurrentSnapshot: async () => ({
+      mediaId: 21,
+      mediaTitle: 'ONE PIECE',
+      entryCount: 4000,
+      fromCache: false,
+      updatedAt: 1000,
+    }),
+    buildMergedDictionary: async () => ({
+      zipPath: path.join(userDataPath, 'character-dictionaries', 'missing.zip'),
+      revision: 'rev-21',
+      dictionaryTitle: 'SubMiner Character Dictionary',
+      entryCount: 4000,
+    }),
+    getYomitanDictionaryInfo: async () => [],
+    importYomitanDictionary: () => new Promise<boolean>(() => {}),
+    deleteYomitanDictionary: async () => true,
+    upsertYomitanDictionarySettings: async () => true,
+    now: () => 1000,
+    dictionaryImportTimeoutBaseMs: 20,
+    onSyncStatus: (event) => {
+      events.push({ phase: event.phase, message: event.message });
+    },
+  });
+
+  await assert.rejects(
+    runtime.runSyncNow(),
+    /importYomitanDictionary\(missing\.zip\) timed out after 20ms/,
+  );
+  assert.equal(events.at(-1)?.phase, 'failed');
+});
+
+test('auto sync ticks the importing notification while the import runs', async () => {
+  const userDataPath = makeTempDir();
+  const events: Array<{ phase: string; message: string }> = [];
+  const scheduled: Array<() => void> = [];
+  const importDeferred = createDeferred<boolean>();
+  let clock = 1000;
+
+  const runtime = createCharacterDictionaryAutoSyncRuntimeService({
+    userDataPath,
+    getConfig: () => ({ enabled: true, maxLoaded: 3, profileScope: 'all' }),
+    getOrCreateCurrentSnapshot: async () => ({
+      mediaId: 21,
+      mediaTitle: 'ONE PIECE',
+      entryCount: 4000,
+      fromCache: false,
+      updatedAt: 1000,
+    }),
+    buildMergedDictionary: async () => ({
+      zipPath: '/tmp/merged.zip',
+      revision: 'rev-21',
+      dictionaryTitle: 'SubMiner Character Dictionary',
+      entryCount: 4000,
+    }),
+    getYomitanDictionaryInfo: async () => [],
+    importYomitanDictionary: () => importDeferred.promise,
+    deleteYomitanDictionary: async () => true,
+    upsertYomitanDictionarySettings: async () => true,
+    now: () => clock,
+    schedule: (fn) => {
+      scheduled.push(fn);
+      return 0 as unknown as ReturnType<typeof setTimeout>;
+    },
+    clearSchedule: () => undefined,
+    onSyncStatus: (event) => {
+      events.push({ phase: event.phase, message: event.message });
+    },
+  });
+
+  const syncPromise = runtime.runSyncNow();
+  await waitUntil(
+    () => events.some((event) => event.phase === 'importing'),
+    'the importing status event',
+  );
+
+  clock = 1000 + 65_000;
+  // The importing heartbeat is the most recently scheduled tick.
+  scheduled.at(-1)!();
+
+  assert.deepEqual(events.at(-1), {
+    phase: 'importing',
+    message: 'Importing character dictionary for ONE PIECE (1m 05s)...',
+  });
+
+  importDeferred.resolve(true);
+  await syncPromise;
+  assert.equal(events.at(-1)?.phase, 'ready');
+});
+
+test('auto sync reports character and image counts while generating a snapshot', async () => {
+  const userDataPath = makeTempDir();
+  const events: Array<{ phase: string; message: string }> = [];
+  let clock = 1000;
+  let importedRevision: string | null = null;
+
+  const runtime = createCharacterDictionaryAutoSyncRuntimeService({
+    userDataPath,
+    getConfig: () => ({ enabled: true, maxLoaded: 3, profileScope: 'all' }),
+    getOrCreateCurrentSnapshot: async (_targetPath, progress) => {
+      progress?.onGenerating?.({ mediaId: 21, mediaTitle: 'ONE PIECE' });
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'characters',
+        completed: 50,
+        total: null,
+        page: 12,
+      });
+      // Same stage, same clock tick: throttled away so a 33-page fetch cannot spam the overlay.
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'characters',
+        completed: 100,
+        total: null,
+        page: 13,
+      });
+      // A stage change always reports, throttle window or not.
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'images',
+        completed: 1,
+        total: 1220,
+      });
+      clock += 2000;
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'images',
+        completed: 240,
+        total: 1220,
+      });
+      clock += 6000;
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'names',
+        completed: 800,
+        total: 1220,
+      });
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'saving',
+        completed: 0,
+        total: null,
+      });
+      return {
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        entryCount: 4000,
+        fromCache: false,
+        updatedAt: 1000,
+      };
+    },
+    buildMergedDictionary: async () => ({
+      zipPath: '/tmp/merged.zip',
+      revision: 'rev-21',
+      dictionaryTitle: 'SubMiner Character Dictionary',
+      entryCount: 4000,
+    }),
+    getYomitanDictionaryInfo: async () =>
+      importedRevision
+        ? [{ title: 'SubMiner Character Dictionary', revision: importedRevision }]
+        : [],
+    importYomitanDictionary: async () => {
+      importedRevision = 'rev-21';
+      return true;
+    },
+    deleteYomitanDictionary: async () => true,
+    upsertYomitanDictionarySettings: async () => true,
+    now: () => clock,
+    onSyncStatus: (event) => {
+      events.push({ phase: event.phase, message: event.message });
+    },
+  });
+
+  await runtime.runSyncNow();
+
+  assert.deepEqual(
+    events.filter((event) => event.phase === 'generating').map((event) => event.message),
+    [
+      'Generating character dictionary for ONE PIECE...',
+      'Generating character dictionary for ONE PIECE (page 12, 50 characters)...',
+      'Generating character dictionary for ONE PIECE (image 1/1220)...',
+      'Generating character dictionary for ONE PIECE (image 240/1220, ~10s left)...',
+      'Generating character dictionary for ONE PIECE (name 800/1220 · 8s)...',
+      'Generating character dictionary for ONE PIECE (saving snapshot · 8s)...',
+    ],
+  );
+});
+
+test('auto sync keeps the generating clock ticking when a stage stalls', async () => {
+  const userDataPath = makeTempDir();
+  const events: Array<{ phase: string; message: string }> = [];
+  const scheduled: Array<() => void> = [];
+  const snapshotDeferred = createDeferred<{
+    mediaId: number;
+    mediaTitle: string;
+    entryCount: number;
+    fromCache: boolean;
+    updatedAt: number;
+  }>();
+  let clock = 1000;
+
+  const runtime = createCharacterDictionaryAutoSyncRuntimeService({
+    userDataPath,
+    getConfig: () => ({ enabled: true, maxLoaded: 3, profileScope: 'all' }),
+    getOrCreateCurrentSnapshot: async (_targetPath, progress) => {
+      progress?.onGenerating?.({ mediaId: 21, mediaTitle: 'ONE PIECE' });
+      progress?.onGenerateProgress?.({
+        mediaId: 21,
+        mediaTitle: 'ONE PIECE',
+        stage: 'images',
+        completed: 240,
+        total: 1220,
+      });
+      return await snapshotDeferred.promise;
+    },
+    buildMergedDictionary: async () => ({
+      zipPath: '/tmp/merged.zip',
+      revision: 'rev-21',
+      dictionaryTitle: 'SubMiner Character Dictionary',
+      entryCount: 4000,
+    }),
+    getYomitanDictionaryInfo: async () => [],
+    importYomitanDictionary: async () => true,
+    deleteYomitanDictionary: async () => true,
+    upsertYomitanDictionarySettings: async () => true,
+    now: () => clock,
+    schedule: (fn) => {
+      scheduled.push(fn);
+      return 0 as unknown as ReturnType<typeof setTimeout>;
+    },
+    clearSchedule: () => undefined,
+    onSyncStatus: (event) => {
+      events.push({ phase: event.phase, message: event.message });
+    },
+  });
+
+  const syncPromise = runtime.runSyncNow();
+  await waitUntil(() => scheduled.length > 0, 'the generating heartbeat');
+
+  // No further progress arrives: only the clock moves.
+  clock += 95_000;
+  scheduled.at(-1)!();
+
+  assert.deepEqual(events.at(-1), {
+    phase: 'generating',
+    message: 'Generating character dictionary for ONE PIECE (image 240/1220 · 1m 35s)...',
+  });
+
+  snapshotDeferred.resolve({
+    mediaId: 21,
+    mediaTitle: 'ONE PIECE',
+    entryCount: 4000,
+    fromCache: false,
+    updatedAt: 1000,
+  });
+  await syncPromise;
+  assert.equal(events.at(-1)?.phase, 'ready');
+});
+
+test('auto sync rebuilds instead of importing a cached merged ZIP with a mismatched revision', async () => {
+  const userDataPath = makeTempDir();
+  const dictionariesDir = path.join(userDataPath, 'character-dictionaries');
+  fs.mkdirSync(dictionariesDir, { recursive: true });
+  const statePath = path.join(dictionariesDir, 'auto-sync-state.json');
+  fs.writeFileSync(
+    statePath,
+    JSON.stringify({
+      activeMediaIds: ['7 - Frieren'],
+      mergedRevision: 'rev-7',
+      mergedDictionaryTitle: 'SubMiner Character Dictionary',
+    }),
+    'utf8',
+  );
+  // Left over from an interrupted run: the archive on disk is not the revision state recorded.
+  buildDictionaryZip(
+    path.join(dictionariesDir, 'merged.zip'),
+    'SubMiner Character Dictionary',
+    'Character names',
+    'rev-stale',
+    [{ term: 'フリーレン', reading: 'フリーレン', role: 'main', glossary: [] } as never],
+    [],
+  );
+  const mergedBuilds: number[][] = [];
+  const imports: string[] = [];
+
+  const runtime = createCharacterDictionaryAutoSyncRuntimeService({
+    userDataPath,
+    getConfig: () => ({ enabled: true, maxLoaded: 3, profileScope: 'all' }),
+    getOrCreateCurrentSnapshot: async () => ({
+      mediaId: 7,
+      mediaTitle: 'Frieren',
+      entryCount: 100,
+      fromCache: true,
+      updatedAt: 1000,
+    }),
+    buildMergedDictionary: async (mediaIds) => {
+      mergedBuilds.push([...mediaIds]);
+      return {
+        zipPath: '/tmp/rebuilt-merged.zip',
+        revision: 'rev-7',
+        dictionaryTitle: 'SubMiner Character Dictionary',
+        entryCount: 100,
+      };
+    },
+    // Yomitan does not have the dictionary, so the sync has to import despite the cached state.
+    getYomitanDictionaryInfo: async () => [],
+    importYomitanDictionary: async (zipPath) => {
+      imports.push(zipPath);
+      return true;
+    },
+    deleteYomitanDictionary: async () => true,
+    upsertYomitanDictionarySettings: async () => true,
+    now: () => 1000,
+  });
+
+  await runtime.runSyncNow();
+
+  assert.deepEqual(mergedBuilds, [[7]]);
+  assert.deepEqual(imports, ['/tmp/rebuilt-merged.zip']);
+});

src/main/runtime/character-dictionary-auto-sync.ts

@@ -1,13 +1,29 @@
 import * as fs from 'fs';
 import * as path from 'path';
 import { ensureDir } from '../../shared/fs-utils';
+import {
+  buildBuildingMessage,
+  buildCheckingMessage,
+  buildFailedMessage,
+  buildGeneratingMessage,
+  buildImportingMessage,
+  buildReadyMessage,
+  formatCharacterDictionaryProgressDetail,
+  joinGeneratingDetail,
+} from './character-dictionary-auto-sync-messages';
+import { readDictionaryZipRevision } from '../character-dictionary-runtime/zip';
 import type { AnilistCharacterDictionaryProfileScope } from '../../types';
 import type {
   CharacterDictionarySnapshotProgressCallbacks,
   CharacterDictionarySnapshotResult,
+  CharacterDictionarySnapshotStageProgress,
   MergedCharacterDictionaryBuildResult,
 } from '../character-dictionary-runtime';
 
+const DEFAULT_IMPORT_TIMEOUT_BASE_MS = 120_000;
+const IMPORT_TIMEOUT_MS_PER_MB = 6_000;
+const IMPORT_TIMEOUT_MAX_MS = 1_800_000;
+
 type AutoSyncMediaEntry = {
   mediaId: number;
   label: string;
@@ -72,7 +88,15 @@ export interface CharacterDictionaryAutoSyncRuntimeDeps {
   now: () => number;
   schedule?: (fn: () => void, delayMs: number) => ReturnType<typeof setTimeout>;
   clearSchedule?: (timer: ReturnType<typeof setTimeout>) => void;
+  /** Budget for the quick Yomitan queries (dictionary info, settings upsert). */
   operationTimeoutMs?: number;
+  /**
+   * Base budget for the slow Yomitan mutations (delete + import). The effective budget grows with
+   * the merged ZIP size, because importing a large dictionary can take several minutes.
+   */
+  dictionaryImportTimeoutBaseMs?: number;
+  heartbeatMs?: number;
+  progressThrottleMs?: number;
   logInfo?: (message: string) => void;
   logWarn?: (message: string) => void;
   onSyncStatus?: (event: CharacterDictionaryAutoSyncStatusEvent) => void;
@@ -345,37 +369,6 @@ function sameMembership(left: number[], right: number[]): boolean {
   return arraysEqual(leftSorted, rightSorted);
 }
 
-function buildSyncingMessage(mediaTitle: string): string {
-  return `Updating character dictionary for ${mediaTitle}...`;
-}
-
-function buildCheckingMessage(mediaTitle: string): string {
-  return `Checking character dictionary for ${mediaTitle}...`;
-}
-
-function buildGeneratingMessage(mediaTitle: string): string {
-  return `Generating character dictionary for ${mediaTitle}...`;
-}
-
-function buildImportingMessage(mediaTitle: string): string {
-  return `Importing character dictionary for ${mediaTitle}...`;
-}
-
-function buildBuildingMessage(mediaTitle: string): string {
-  return `Building character dictionary for ${mediaTitle}...`;
-}
-
-function buildReadyMessage(mediaTitle: string): string {
-  return `Character dictionary ready for ${mediaTitle}`;
-}
-
-function buildFailedMessage(mediaTitle: string | null, errorMessage: string): string {
-  if (mediaTitle) {
-    return `Character dictionary sync failed for ${mediaTitle}: ${errorMessage}`;
-  }
-  return `Character dictionary sync failed: ${errorMessage}`;
-}
-
 export function createCharacterDictionaryAutoSyncRuntimeService(
   deps: CharacterDictionaryAutoSyncRuntimeDeps,
 ): {
@@ -389,21 +382,31 @@ export function createCharacterDictionaryAutoSyncRuntimeService(
   const clearSchedule = deps.clearSchedule ?? ((timer) => clearTimeout(timer));
   const debounceMs = 800;
   const operationTimeoutMs = Math.max(1, Math.floor(deps.operationTimeoutMs ?? 7_000));
+  const dictionaryImportTimeoutBaseMs = Math.max(
+    1,
+    Math.floor(deps.dictionaryImportTimeoutBaseMs ?? DEFAULT_IMPORT_TIMEOUT_BASE_MS),
+  );
+  const heartbeatMs = Math.max(1, Math.floor(deps.heartbeatMs ?? 5_000));
+  const progressThrottleMs = Math.max(0, Math.floor(deps.progressThrottleMs ?? 1_000));
 
   let debounceTimer: ReturnType<typeof setTimeout> | null = null;
   let syncInFlight = false;
   let runQueued = false;
   let activeCurrentMediaId: number | null = null;
 
-  const withOperationTimeout = async <T>(label: string, promise: Promise<T>): Promise<T> => {
+  const withTimeout = async <T>(
+    label: string,
+    promise: Promise<T>,
+    timeoutMs: number,
+  ): Promise<T> => {
     let timer: ReturnType<typeof setTimeout> | null = null;
     try {
       return await Promise.race([
         promise,
         new Promise<never>((_resolve, reject) => {
           timer = setTimeout(() => {
-            reject(new Error(`${label} timed out after ${operationTimeoutMs}ms`));
-          }, operationTimeoutMs);
+            reject(new Error(`${label} timed out after ${timeoutMs}ms`));
+          }, timeoutMs);
         }),
       ]);
     } finally {
@@ -413,6 +416,57 @@ export function createCharacterDictionaryAutoSyncRuntimeService(
     }
   };
 
+  const withOperationTimeout = <T>(label: string, promise: Promise<T>): Promise<T> =>
+    withTimeout(label, promise, operationTimeoutMs);
+
+  /**
+   * Importing a merged dictionary means Yomitan writing every term and image into IndexedDB, which
+   * scales with the ZIP: a single-season dictionary lands in seconds, One Piece takes minutes. Size
+   * the budget off the archive instead of failing a healthy import on a flat deadline.
+   */
+  const resolveImportTimeoutMs = (zipPath: string | null): number => {
+    let bytes = 0;
+    if (zipPath) {
+      try {
+        bytes = fs.statSync(zipPath).size;
+      } catch {
+        bytes = 0;
+      }
+    }
+    const sizeAllowanceMs = (bytes / (1024 * 1024)) * IMPORT_TIMEOUT_MS_PER_MB;
+    return Math.min(
+      IMPORT_TIMEOUT_MAX_MS,
+      Math.max(
+        dictionaryImportTimeoutBaseMs,
+        Math.round(dictionaryImportTimeoutBaseMs + sizeAllowanceMs),
+      ),
+    );
+  };
+
+  /** Keeps the persistent notification ticking so a multi-minute import never looks hung. */
+  const withHeartbeat = async <T>(
+    run: () => Promise<T>,
+    onTick: (elapsedMs: number) => void,
+  ): Promise<T> => {
+    const startedAt = deps.now();
+    let stopped = false;
+    let timer: ReturnType<typeof setTimeout> | null = null;
+    const tick = (): void => {
+      if (stopped) return;
+      onTick(deps.now() - startedAt);
+      timer = schedule(tick, heartbeatMs);
+    };
+    timer = schedule(tick, heartbeatMs);
+    try {
+      return await run();
+    } finally {
+      stopped = true;
+      if (timer !== null) {
+        clearSchedule(timer);
+      }
+    }
+  };
+
   const runSyncOnce = async (): Promise<void> => {
     const config = deps.getConfig();
     if (!config.enabled) {
@@ -422,33 +476,112 @@ export function createCharacterDictionaryAutoSyncRuntimeService(
 
     let currentMediaId: number | undefined;
     let currentMediaTitle: string | null = null;
+    let lastProgressAt = Number.NEGATIVE_INFINITY;
+    let lastProgressStage: CharacterDictionarySnapshotStageProgress['stage'] | null = null;
+    let generating: {
+      mediaId: number;
+      mediaTitle: string;
+      startedAt: number;
+      detail: string | null;
+    } | null = null;
+    let imageRate: { startedAt: number; startCompleted: number } | null = null;
+
+    const emitGeneratingStatus = (): void => {
+      if (!generating) {
+        return;
+      }
+      deps.onSyncStatus?.({
+        phase: 'generating',
+        mediaId: generating.mediaId,
+        mediaTitle: generating.mediaTitle,
+        message: buildGeneratingMessage(
+          generating.mediaTitle,
+          joinGeneratingDetail(generating.detail, deps.now() - generating.startedAt),
+        ),
+      });
+    };
+
+    // Image downloads are serial and evenly paced, so the observed rate predicts the tail well.
+    const estimateRemainingImageMs = (
+      progress: CharacterDictionarySnapshotStageProgress,
+      nowMs: number,
+    ): number | null => {
+      if (progress.stage !== 'images' || progress.total === null || imageRate === null) {
+        return null;
+      }
+      const done = progress.completed - imageRate.startCompleted;
+      const elapsedMs = nowMs - imageRate.startedAt;
+      const remaining = progress.total - progress.completed;
+      if (done <= 0 || elapsedMs <= 0 || remaining <= 0) {
+        return null;
+      }
+      return Math.round((elapsedMs / done) * remaining);
+    };
 
     try {
       deps.logInfo?.('[dictionary:auto-sync] syncing current anime snapshot');
-      const snapshot = await deps.getOrCreateCurrentSnapshot(undefined, {
-        onChecking: ({ mediaId, mediaTitle }) => {
-          currentMediaId = mediaId;
-          currentMediaTitle = mediaTitle;
-          activeCurrentMediaId = mediaId;
-          deps.onSyncStatus?.({
-            phase: 'checking',
-            mediaId,
-            mediaTitle,
-            message: buildCheckingMessage(mediaTitle),
-          });
-        },
-        onGenerating: ({ mediaId, mediaTitle }) => {
-          currentMediaId = mediaId;
-          currentMediaTitle = mediaTitle;
-          activeCurrentMediaId = mediaId;
-          deps.onSyncStatus?.({
-            phase: 'generating',
-            mediaId,
-            mediaTitle,
-            message: buildGeneratingMessage(mediaTitle),
-          });
-        },
-      });
+      const snapshot = await withHeartbeat(
+        () =>
+          deps.getOrCreateCurrentSnapshot(undefined, {
+            onChecking: ({ mediaId, mediaTitle }) => {
+              currentMediaId = mediaId;
+              currentMediaTitle = mediaTitle;
+              activeCurrentMediaId = mediaId;
+              deps.onSyncStatus?.({
+                phase: 'checking',
+                mediaId,
+                mediaTitle,
+                message: buildCheckingMessage(mediaTitle),
+              });
+            },
+            onGenerating: ({ mediaId, mediaTitle }) => {
+              currentMediaId = mediaId;
+              currentMediaTitle = mediaTitle;
+              activeCurrentMediaId = mediaId;
+              lastProgressAt = Number.NEGATIVE_INFINITY;
+              lastProgressStage = null;
+              imageRate = null;
+              generating = { mediaId, mediaTitle, startedAt: deps.now(), detail: null };
+              emitGeneratingStatus();
+            },
+            // Long-running work (AniList character pages, then one image download per character
+            // and voice actor, then MeCab name splits) reports counts so the notification shows
+            // movement instead of a frozen "Generating..." for the minutes a large series takes.
+            onGenerateProgress: (progress) => {
+              const nowMs = deps.now();
+              if (!generating) {
+                generating = {
+                  mediaId: progress.mediaId,
+                  mediaTitle: progress.mediaTitle,
+                  startedAt: nowMs,
+                  detail: null,
+                };
+              }
+              if (progress.stage === 'images' && imageRate === null) {
+                imageRate = { startedAt: nowMs, startCompleted: progress.completed };
+              }
+              // Stage changes and the last item of a stage always report; the throttle only thins
+              // out the run of identical-looking updates in between.
+              const isFinal = progress.total !== null && progress.completed >= progress.total;
+              const isStageChange = progress.stage !== lastProgressStage;
+              if (!isFinal && !isStageChange && nowMs - lastProgressAt < progressThrottleMs) {
+                return;
+              }
+              lastProgressAt = nowMs;
+              lastProgressStage = progress.stage;
+              generating.mediaId = progress.mediaId;
+              generating.mediaTitle = progress.mediaTitle;
+              generating.detail = formatCharacterDictionaryProgressDetail(
+                progress,
+                estimateRemainingImageMs(progress, nowMs),
+              );
+              emitGeneratingStatus();
+            },
+          }),
+        // Ticks even when a step stalls, so the message keeps moving while the counts do not.
+        () => emitGeneratingStatus(),
+      );
+      generating = null;
       currentMediaId = snapshot.mediaId;
       currentMediaTitle = snapshot.mediaTitle;
       activeCurrentMediaId = snapshot.mediaId;
@@ -531,33 +664,61 @@ export function createCharacterDictionaryAutoSyncRuntimeService(
           mediaTitle: snapshot.mediaTitle,
           message: buildImportingMessage(snapshot.mediaTitle),
         });
-        if (existing !== null) {
-          await withOperationTimeout(
-            `deleteYomitanDictionary(${dictionaryTitle})`,
-            deps.deleteYomitanDictionary(dictionaryTitle),
-          );
-        }
-        if (merged === null) {
-          const existingMergedZipPath = path.join(dictionariesDir, 'merged.zip');
-          if (fs.existsSync(existingMergedZipPath)) {
-            merged = {
-              zipPath: existingMergedZipPath,
-              revision,
-              dictionaryTitle,
-              entryCount: snapshot.entryCount,
-            };
-          } else {
-            merged = await deps.buildMergedDictionary(nextActiveMediaIdValues);
-          }
-        }
-        deps.logInfo?.(`[dictionary:auto-sync] importing merged dictionary: ${merged.zipPath}`);
-        const imported = await withOperationTimeout(
-          `importYomitanDictionary(${path.basename(merged.zipPath)})`,
-          deps.importYomitanDictionary(merged.zipPath),
+        await withHeartbeat(
+          async () => {
+            const importTimeoutMs = resolveImportTimeoutMs(
+              merged?.zipPath ?? path.join(dictionariesDir, 'merged.zip'),
+            );
+            if (existing !== null) {
+              await withTimeout(
+                `deleteYomitanDictionary(${dictionaryTitle})`,
+                deps.deleteYomitanDictionary(dictionaryTitle),
+                importTimeoutMs,
+              );
+            }
+            if (merged === null) {
+              // The cached archive only stands in for the recorded state when its own index.json
+              // agrees. A stale or half-written ZIP would be imported under the wrong revision,
+              // and every later sync would then see a revision mismatch and re-import it.
+              const existingMergedZipPath = path.join(dictionariesDir, 'merged.zip');
+              const existingMergedRevision = readDictionaryZipRevision(existingMergedZipPath);
+              if (existingMergedRevision === revision) {
+                merged = {
+                  zipPath: existingMergedZipPath,
+                  revision,
+                  dictionaryTitle,
+                  entryCount: snapshot.entryCount,
+                };
+              } else {
+                deps.logInfo?.(
+                  `[dictionary:auto-sync] cached merged ZIP unusable (revision ${existingMergedRevision ?? 'unreadable'}, expected ${revision}); rebuilding`,
+                );
+                merged = await deps.buildMergedDictionary(nextActiveMediaIdValues);
+              }
+            }
+            const mergedZipPath = merged.zipPath;
+            const mergedImportTimeoutMs = resolveImportTimeoutMs(mergedZipPath);
+            deps.logInfo?.(
+              `[dictionary:auto-sync] importing merged dictionary: ${mergedZipPath} (timeout ${mergedImportTimeoutMs}ms)`,
+            );
+            const imported = await withTimeout(
+              `importYomitanDictionary(${path.basename(mergedZipPath)})`,
+              deps.importYomitanDictionary(mergedZipPath),
+              mergedImportTimeoutMs,
+            );
+            if (!imported) {
+              throw new Error(`Failed to import dictionary ZIP: ${merged.zipPath}`);
+            }
+          },
+          (elapsedMs) => {
+            deps.onSyncStatus?.({
+              phase: 'importing',
+              mediaId: snapshot.mediaId,
+              mediaTitle: snapshot.mediaTitle,
+              message: buildImportingMessage(snapshot.mediaTitle, elapsedMs),
+            });
+          },
         );
-        if (!imported) {
-          throw new Error(`Failed to import dictionary ZIP: ${merged.zipPath}`);
-        }
         changed = true;
       }
 

src/main/runtime/startup-osd-sequencer.ts

@@ -10,7 +10,7 @@ export interface StartupOsdSequencerDeps {
   getNotificationType?: () => NotificationType | undefined;
   showOsd: (message: string) => boolean | void;
   showOverlayNotification?: (payload: OverlayNotificationPayload) => void;
-  showDesktopNotification?: (title: string, options: { body?: string }) => void;
+  showDesktopNotification?: (title: string, options: { body?: string; replaceId?: string }) => void;
 }
 
 interface StartupStatusNotificationOptions {
@@ -62,7 +62,11 @@ export function createStartupOsdSequencer(deps: StartupOsdSequencerDeps): {
       shown = deps.showOsd(options.message) !== false || shown;
     }
     if (options.desktop !== false && shouldShowDesktop(type)) {
-      deps.showDesktopNotification?.('SubMiner', { body: options.message });
+      // Each startup lane keeps one live desktop notification instead of one per update.
+      deps.showDesktopNotification?.('SubMiner', {
+        body: options.message,
+        replaceId: options.id,
+      });
       shown = true;
     }
     return shown;

src/shared/stored-zip.ts

@@ -148,6 +148,145 @@ function createEndOfCentralDirectory(
   return end;
 }
 
+const LOCAL_FILE_HEADER_SIGNATURE = 0x04034b50;
+const LOCAL_FILE_HEADER_SIZE = 30;
+const END_OF_CENTRAL_DIRECTORY_SIGNATURE = 0x06054b50;
+const END_OF_CENTRAL_DIRECTORY_SIZE = 22;
+const CENTRAL_FILE_HEADER_SIGNATURE = 0x02014b50;
+const CENTRAL_FILE_HEADER_SIZE = 46;
+// 65535 entries with names of a few dozen bytes stay far under this; the cap only stops a corrupt
+// record length from asking for an allocation the size of the archive.
+const MAX_CENTRAL_DIRECTORY_BYTES = 16 * 1024 * 1024;
+
+/**
+ * Walks every declared central-directory record, checking each signature and keeping the
+ * variable-length name/extra/comment fields inside the directory. The walk has to land exactly on
+ * the end of the directory, so a record that was overwritten in place fails even though the file
+ * kept its size.
+ */
+function isCentralDirectoryIntact(
+  fd: number,
+  centralStart: number,
+  centralSize: number,
+  entryCount: number,
+): boolean {
+  if (centralSize === 0 || centralSize > MAX_CENTRAL_DIRECTORY_BYTES) {
+    return false;
+  }
+  const central = Buffer.alloc(centralSize);
+  if (fs.readSync(fd, central, 0, centralSize, centralStart) !== centralSize) {
+    return false;
+  }
+
+  let cursor = 0;
+  for (let index = 0; index < entryCount; index += 1) {
+    if (cursor + CENTRAL_FILE_HEADER_SIZE > centralSize) {
+      return false;
+    }
+    if (central.readUInt32LE(cursor) !== CENTRAL_FILE_HEADER_SIGNATURE) {
+      return false;
+    }
+    const nameLength = central.readUInt16LE(cursor + 28);
+    const extraLength = central.readUInt16LE(cursor + 30);
+    const commentLength = central.readUInt16LE(cursor + 32);
+    cursor += CENTRAL_FILE_HEADER_SIZE + nameLength + extraLength + commentLength;
+    if (cursor > centralSize) {
+      return false;
+    }
+  }
+  return cursor === centralSize;
+}
+
+/**
+ * Start of the central directory, or null when the archive is not a complete one of ours. The
+ * end-of-central-directory record is written last, so finding an intact one is what separates a
+ * finished archive from a half-written one.
+ */
+function readCentralDirectoryStart(fd: number, fileSize: number): number | null {
+  if (fileSize < END_OF_CENTRAL_DIRECTORY_SIZE) {
+    return null;
+  }
+  const end = Buffer.alloc(END_OF_CENTRAL_DIRECTORY_SIZE);
+  const endOffset = fileSize - END_OF_CENTRAL_DIRECTORY_SIZE;
+  if (fs.readSync(fd, end, 0, end.length, endOffset) !== end.length) {
+    return null;
+  }
+  // writeStoredZip never writes an archive comment, so the record is exactly the last 22 bytes.
+  if (end.readUInt32LE(0) !== END_OF_CENTRAL_DIRECTORY_SIGNATURE || end.readUInt16LE(20) !== 0) {
+    return null;
+  }
+  const entryCount = end.readUInt16LE(10);
+  if (entryCount === 0) {
+    return null;
+  }
+  const centralSize = end.readUInt32LE(12);
+  const centralStart = end.readUInt32LE(16);
+  if (centralStart + centralSize !== endOffset) {
+    return null;
+  }
+  if (!isCentralDirectoryIntact(fd, centralStart, centralSize, entryCount)) {
+    return null;
+  }
+  return centralStart;
+}
+
+/**
+ * Reads the first entry of an archive written by {@link writeStoredZip}: every entry is stored
+ * uncompressed with no extra field and no data descriptor, so the leading local header is enough.
+ * Returns null for anything it does not recognize, so callers treat a corrupt, truncated, or
+ * foreign archive the same as a missing one.
+ */
+export function readStoredZipFirstFile(zipPath: string): StoredZipFile | null {
+  let fd: number;
+  try {
+    fd = fs.openSync(zipPath, 'r');
+  } catch {
+    return null;
+  }
+
+  try {
+    const fileSize = fs.fstatSync(fd).size;
+    const centralStart = readCentralDirectoryStart(fd, fileSize);
+    if (centralStart === null) {
+      return null;
+    }
+    const header = Buffer.alloc(LOCAL_FILE_HEADER_SIZE);
+    if (fs.readSync(fd, header, 0, header.length, 0) !== header.length) {
+      return null;
+    }
+    if (header.readUInt32LE(0) !== LOCAL_FILE_HEADER_SIGNATURE) {
+      return null;
+    }
+    // Compression method 0 (stored) is the only thing writeStoredZip emits.
+    if (header.readUInt16LE(8) !== 0) {
+      return null;
+    }
+    const entrySize = header.readUInt32LE(18);
+    const nameLength = header.readUInt16LE(26);
+    const extraLength = header.readUInt16LE(28);
+    const dataOffset = LOCAL_FILE_HEADER_SIZE + nameLength + extraLength;
+    if (dataOffset + entrySize > centralStart) {
+      return null;
+    }
+    const name = Buffer.alloc(nameLength);
+    if (
+      nameLength > 0 &&
+      fs.readSync(fd, name, 0, nameLength, LOCAL_FILE_HEADER_SIZE) !== nameLength
+    ) {
+      return null;
+    }
+    const data = Buffer.alloc(entrySize);
+    if (entrySize > 0 && fs.readSync(fd, data, 0, entrySize, dataOffset) !== entrySize) {
+      return null;
+    }
+    return { name: name.toString('utf8'), data };
+  } catch {
+    return null;
+  } finally {
+    fs.closeSync(fd);
+  }
+}
+
 function writeBuffer(fd: number, buffer: Buffer): void {
   let written = 0;
   while (written < buffer.length) {