The missing-pin warning lived in the per-message drop path behind a
process-wide class bool. That hid it twice over (r1 2ab/2c Medium):
- a second unpinned mailbox in the same process (multiplex) never
warned once the first had tripped the flag;
- pairing/decline-only deployments never warned at all, because a
first-contact sender is not granted and its drop logs at debug.
A missing pin is account config, not something one sender did, so
connect() now names the fix once per account after the IMAP/SMTP
probes succeed, skipping reconnect-watcher retries (is_reconnect).
Pinned or opted-out accounts stay quiet. The per-message drop path is
back to main's rule: a listed sender's drop warns (with the reason, no
hint), an unlisted one logs at debug, so it is never noisier than main.
de6013bcef