The set-once key guard made a lost passphrase a permanent wall (409 on re-setup,
KeyGate offered only unlock/setup). Add an escape hatch:
- POST /api/messages/keys/reset drops the user's MessageKey so a new passphrase
can be set. Because every conversation key is derived from the keypair,
replacing it orphans all stored ciphertext in both directions, so the now-dead
`user` messages are deleted too (clean slate; system messages untouched).
Password accounts must re-verify (a hijacked session must not silently reset
messaging and read future messages); Google-only accounts rely on the session
+ the client danger-confirm. Rate-limited per user.
- KeyGate gains a "Forgot passphrase?" path in unlock mode → a danger reset view
(spells out the permanent history loss; a current-password field for password
accounts) → resets and returns to a fresh setup.
- e2ee.resetLocal wipes this device's key + derived conversation keys + the
IndexedDB copy; api.resetMessageKey; HU/EN strings.
peter
1119eb0218