- remove stale docs/admin-frontend-spec.md (old Express/EJS admin), unused templates/ (SmartAdmin copy), dead scripts/sync-agents.cjs, committed dev.pid
- add docs/API.md (admin REST API reference) and docs/DATABASE.md (DB schema)
- refresh .env.example: drop stale ADMIN_PORT/SHOP_CONTAINER, add ADMIN_URL, HEALTH_PORT, DEFAULT_LANGUAGE, CHATBOT_API_*
- add npm run lint so Gitea workflows pass
- rebrand web-testing suite from APAW to telegram-shop
