Ilia Denisov
e22f4b7800
Replaces the LangUndetermined placeholder with whatlanggo-backed body detection on every send path, then adds a translation cache keyed on (message_id, target_lang) populated lazily on the per-message read endpoint. The noop translator that ships with Stage D returns engine="noop", which the service treats as "translation unavailable" — wiring a real backend (LibreTranslate HTTP client is the documented next step) is a one-file swap. GetMessage and ListInbox now accept a targetLang argument; the HTTP layer resolves the caller's accounts.preferred_language and forwards it. Inbox uses the cache only (never calls the translator) so bulk reads stay fast under future SaaS backends. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>