Backoffice stage 5: products, broadcasts, activity log, settings

- Products: services with full setup — content (name, description, extras names
  in 5 languages via text overrides), price tiers and extras, booking window,
  late-cancel fee, on/off, checklist; category discounts by membership level;
  membership plan prices; promo codes; relocation steps and documents.
- Text overrides: TextOverride table on top of the i18n files; API, bots and the
  worker reload them every minute, mini apps fetch public.texts at start.
- Promo codes applied to orders (admin new-order form and client API): not
  stacked with membership discount — the larger wins; once per client; validity,
  limit and categories.
- Broadcasts to the client bot by any client filter, per-language texts with
  Russian fallback, test to yourself, ~25 msg/s, per-recipient status, resume after
  worker restart, history with progress and stop.
- Activity log (who/when/what, filters, details) and Settings page with all
  owner settings grouped, plus payment methods.
- Tests for promo codes and text overrides.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/api/package.json

@@ -23,6 +23,7 @@
     "@aws-sdk/s3-request-presigner": "^3.1152.0",
     "@barev/core": "workspace:*",
     "@barev/db": "workspace:*",
+    "@barev/i18n": "workspace:*",
     "@barev/services": "workspace:*",
     "@fastify/cookie": "^11.0.0",
     "@fastify/cors": "^11.1.0",