feat(01-12): wave-3 task-1 — manifest i18n (__MSG_*__ + default_locale='en') + _locales/{en,ru}/messages.json (16 keys; D-07 + D-08 baked in)

manifest.json migrated to chrome i18n placeholders:
- name: 'AI Call Recorder' → '__MSG_extName__'
- description: 'Запись сессий операторов для диагностики ошибок' → '__MSG_extDesc__'
- default_locale: 'en' (new field per RESEARCH §11 + Pitfall 4 fallback chain)
- action.default_title: '__MSG_tooltipOff__' (new field per Brief §02 string #1)

_locales/en/messages.json + _locales/ru/messages.json each carry the
same 16-key matrix per RESEARCH §10 + Brief §02 verbatim + D-07 user
override + D-08 tagline:

  extName, extDesc, tooltipOff, tooltipRecPrefix, tooltipErr,
  popupSavePrompt, popupSaveCta, popupSaveDone, popupSaving,
  popupSaveDoneShort, popupEmptyState, popupInfoText,
  notifStartup, notifRecovery, welcomeHeroRu, welcomeHeroEn

Canonical values (per brand-decisions-v1.md + RESEARCH §10 Brief §02):
- EN extName = 'Mokosh — Session Capture' (D-07 user override of A)
- EN extDesc = 'Thirty seconds ago, always at hand.' (D-08 tagline)
- RU extName = 'Mokosh — Запись сессии'
- RU extDesc = 'Тридцать секунд назад, всегда под рукой.'

NB on key count: the artifact-table 12-key baseline excluded the three
Wave-4 deltas (popupSaving, popupSaveDoneShort, popupEmptyState) which
are introduced now to avoid a re-locale-parity flap when Wave 4 lands.
popupInfoText is present in BOTH locales (the plan-checker flag 1
informational scope-slip is corrected here — see deviation block below).
Plan success-criteria reading: ≥12 keys with Wave 4 additive deltas
accounted for.

Each key carries both `message` and `description` per Chrome i18n
schema. EN descriptions are translator-facing; RU descriptions are
plain-Russian context for native operators.

npm run build emits:
- dist/manifest.json carries the i18n shape verbatim (crxjs preserves
  __MSG_* placeholders; Chrome's manifest loader resolves them at install)
- dist/_locales/en/messages.json (3.30 KB)
- dist/_locales/ru/messages.json (3.81 KB)

Verification:
- tests/i18n/manifest-i18n.test.ts: 10/10 GREEN
- tests/i18n/locale-parity.test.ts: 4/4 GREEN (en↔ru parity, non-empty
  messages, 16 keys each)
- tests/build/no-remote-fonts.test.ts: 4/4 GREEN (post-build dist/ has
  zero remote font URLs)
- Full vitest sweep: 145/147 GREEN (2 RED remaining are popup/style.css
  tokens-adopted cases — Wave 4 work)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

manifest.json

@@ -1,8 +1,9 @@
 {
   "manifest_version": 3,
-  "name": "AI Call Recorder",
+  "name": "__MSG_extName__",
   "version": "1.0.0",
-  "description": "Запись сессий операторов для диагностики ошибок",
+  "default_locale": "en",
+  "description": "__MSG_extDesc__",
   "permissions": [
     "desktopCapture",
     "activeTab",
@@ -28,6 +29,7 @@
   ],
   "action": {
     "default_popup": "src/popup/index.html",
+    "default_title": "__MSG_tooltipOff__",
     "default_icon": {
       "16": "icons/icon16.png",
       "48": "icons/icon48.png",