A send that the mail provider did not accept finished its background
transaction as ok, so rejected reset emails looked delivered in tracing.
It now finishes as an error with a fixed message that names no recipient.
The channel used DropWrite, under which TryWrite reports success and
discards the email, so a full queue still counted the request and never
sent the code. Wait makes TryWrite return false when the queue is full,
without blocking, so the request is released and the user can ask again.
- Forgot Password is limited to 3 codes an hour and 10 a day per email, and
an account gets 10 failed code checks a day across every code it is sent,
so new client addresses and new codes no longer buy more guesses. Refused
requests answer exactly like accepted ones.
- The reset email is queued to a background sender, and unregistered
addresses store a row no code can match, so both paths do the same work
and return without waiting on the mail provider. Each request also clears
expired codes.
- Code hashes are HMAC-SHA256 under a key derived with HKDF from the JWT
signing secret; rows in the previous unkeyed format stop matching.
- Email and code are read only from the JSON body.
