A failed login keeps its username in the in-memory log buffer, the
limiter table and the notifier queue, and the route accepted any body
the global cap allowed. The login route now takes at most 16 KiB and
answers a username over 256 bytes with the generic failure before any
of those see it; the user setters refuse such a name too, so no stored
username can be one the login route turns away.
A panel or API request rejected for a missing or wrong CSRF token got a bare
403 and left nothing in the log, so an operator chasing failed logins from a
stale tab or a script had no trace. CSRFMiddleware now logs a warning with the
method, path and client address. The address comes from getRemoteIp, which
honours the trusted-proxy list, instead of gin's ClientIP, which trusts any
peer's X-Forwarded-For.