Improve startup dictionary sync UX and default playback keybindings

- Add default `f` fullscreen overlay binding and switch default AniSkip skip key to `Tab`
- Make character-dictionary auto-sync non-blocking at startup with tokenization gating for Yomitan mutations
- Add ordered startup OSD progress (checking/generating/updating/importing), refresh current subtitle on sync completion, and extend regression tests

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

@@ -0,0 +1,92 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  notifyCharacterDictionaryAutoSyncStatus,
+  type CharacterDictionaryAutoSyncNotificationEvent,
+} from './character-dictionary-auto-sync-notifications';
+
+function makeEvent(
+  phase: CharacterDictionaryAutoSyncNotificationEvent['phase'],
+  message: string,
+): CharacterDictionaryAutoSyncNotificationEvent {
+  return {
+    phase,
+    mediaId: 101291,
+    mediaTitle: 'Rascal Does Not Dream of Bunny Girl Senpai',
+    message,
+  };
+}
+
+test('auto sync notifications send osd updates for progress phases', () => {
+  const calls: string[] = [];
+
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('checking', 'checking'), {
+    getNotificationType: () => 'osd',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('generating', 'generating'), {
+    getNotificationType: () => 'osd',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('syncing', 'syncing'), {
+    getNotificationType: () => 'osd',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('importing', 'importing'), {
+    getNotificationType: () => 'osd',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('ready', 'ready'), {
+    getNotificationType: () => 'osd',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+
+  assert.deepEqual(calls, [
+    'osd:checking',
+    'osd:generating',
+    'osd:syncing',
+    'osd:importing',
+    'osd:ready',
+  ]);
+});
+
+test('auto sync notifications never send desktop notifications', () => {
+  const calls: string[] = [];
+
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('syncing', 'syncing'), {
+    getNotificationType: () => 'both',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('importing', 'importing'), {
+    getNotificationType: () => 'both',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('ready', 'ready'), {
+    getNotificationType: () => 'both',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+  notifyCharacterDictionaryAutoSyncStatus(makeEvent('failed', 'failed'), {
+    getNotificationType: () => 'both',
+    showOsd: (message) => calls.push(`osd:${message}`),
+    showDesktopNotification: (title, options) =>
+      calls.push(`desktop:${title}:${options.body ?? ''}`),
+  });
+
+  assert.deepEqual(calls, ['osd:syncing', 'osd:importing', 'osd:ready', 'osd:failed']);
+});