fix(logtail): keep mail.log in /data and reconcile stuck rows (v1.x closure phase 2)

Move the delivery log from the ephemeral /var/log to /data/log/mail.log so
the lines that resolve a queued send-log row survive a container recreate.
postlogd writes it as postfix, the panel reads it through the selfpost group
(dir 2750, file 0640, normalised every start); backups exclude log/.

Close the residual gap with a queue sweep: rows queued for over two minutes
whose id postqueue -p no longer lists are marked bounced. The sweep waits
until the tailer has read the log to its end and does nothing when the queue
cannot be listed, so a message in flight is never touched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

deploy/docker-compose.yml

@@ -54,6 +54,9 @@ services:
       # All persistent state lives under /data (spec 9): SQLite DB, DKIM keys,
       # sasldb2, sender map, setup token. Back this up (panel button or the
       # selfpost-backup CLI) before you touch it directly.
+      # Postfix's mail.log is here too (./data/log, rotated daily, 14 files
+      # kept) so the delivery lines that resolve a queued send-log row survive
+      # a container recreate; it is diagnostics and is left out of backups.
       - ./data:/data
       # Read-only: SelfPost only ever reads certificates, never manages them
       # (spec 10 p.2). Point this at wherever your reverse-proxy/certbot