Swap the translation source

• Interface: MessageSource (load(locale): Promise<Messages>) in packages/i18n/src/index.ts.
• Today: bundledMessages, the JSON in packages/i18n/messages/, type-checked against English. Changing copy needs a deploy.
• Env: none today.

Swap

1. Implement MessageSource over the new store, e.g. a table i18n.message(locale, key, value) (db-change skill), cached in Redis and dropped on write. Validate loaded messages against English's shape and fall back to bundledMessages for missing keys, so a bad row never renders a raw key.
2. Wire it where messages are loaded:
   • Nest services: I18nModule.forRoot({ source }) (packages/nest-common/src/i18n.ts), registered in apps/api/src/app.module.ts and apps/notifications/src/app.module.ts (everything that renders copy injects it with @InjectI18n()). Call i18n.invalidate(locale) on every replica when copy changes (a Redis pub/sub message).
   • apps/web: bundledMessages.load in apps/web/src/i18n/request.ts.
   • apps/mobile: bundledMessages.load in apps/mobile/src/lib/i18n.tsx (keep the bundle as the offline fallback).
3. New variables (the store's URL, cache TTL) in each service's src/env.ts, .env.example and docs/environment.md.

Tests

packages/i18n/src/index.test.ts (loading, caching, invalidation, catalog completeness) with a fake source; packages/email/src/render.test.tsx renders emails through a translator; integration tests for the store in the owning service.

Finish

1. The verify skill.
2. Ask the reviewer agent to review the change, and the security-reviewer agent: a new implementation brings its own credentials and sends data somewhere new. If you wrote a migration, the migration-reviewer agent too.
3. Update the seam's row in the README's "Scaling path" table if what's "Now" changed.