Follow-up hardening from two review passes on the on-device translation
feature:
- Privacy (HIGH): the translation cache is decrypted message plaintext,
but logout did not clear it (unlike the search index), leaving up to
300 cleartext bodies in localStorage on shared devices. Add
clearTranslationCache() and call it from both logout paths
(logoutClient and the server-forced SessionLoggedOut handler).
- Edited messages (MEDIUM): the cache key was eventId:target with no
content dependence, so an edit reused the pre-edit translation. Fold a
content fingerprint into the key, and re-arm the auto-translate
one-shot when the text changes.
- Settings (LOW): coerce a persisted translateTargetLang to a supported
curated code so the hook never targets a language the engine can't
produce (previously only the UI clamped it).
- Chinese (LOW): restore canonical BCP-47 case (zh-Hant / zh-Hans) at
the Translator API boundary, since normalizeLang lowercases the script
subtag for internal keys.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
jaredandClaude Opus 4.8
c77ab346d3