inbound-upstream-result: the upstream's answer in the Inbound log

The owner, 2026-10-16: the Inbound log lacks the upstream's answer - "Не
понятна судьба письма: принято, отклонено, хост не доступен"; the result
in the row only, a page per message later if needed. Mockups 5348330 and
46b90d2, plan 295d72e.

- Migration 0012: inbound_spam_log gains queue_id, upstream_status ('',
  queued, held, sent, deferred, bounced; CHECK), upstream_relay,
  upstream_reply, upstream_at, and a partial index on queue_id. Schema 12.
- The inbound journal milter writes an accepted row with the queue id of
  end-of-message and "queued" ("held" when the filter had it held), the
  recipient as Postfix logs it (recipientAsLogged), after detaching older
  rows of a queue id Postfix uses again; no queue id, no result.
- The tailer: a delivery line no send-log row took goes to the journal -
  status, relay= ("" for none), the reply after the first status=, cut to
  255 printable bytes, the line's time; queued/held/deferred rows only,
  sent and bounced final. qmgr's expiry makes them bounced, keeping the
  last reply. cleanup's "removed (" detaches rows of a message never
  queued. Addresses in delivery lines are read by Postfix's quoting
  (loggedAddress): a quoted RCPT TO cannot end one early.
- The page: an Upstream column - a plain tag for queued and held, else a
  tag opening the host, the reply, when and what follows; "—" for refused
  mail and older rows. Help (word for word with the mockup), guide,
  architecture, security, schema-migrations, CHANGELOG.

Reviewed before the commit (technical and security, 2026-10-16); the plan
lists each finding and what it became.

Tests: store (results, finality, expiry, held, a reused id, the queue-id
index in every plan), milter (queue id, held, quoted recipient, no {i}),
logtail (relay and reply, a forged quoted recipient, Run hands the journal
what the send log did not take, cleanup's removal), view (the column, held,
null sender), e2e (both relayed messages sent with the sink's 250; an
upstream refusing connections deferred with the reason and no host, then
expired to bounced; the refused row has none). go vet + go test (26
packages) and make e2e on the test server for this tree.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/store/migrations/0012_inbound_upstream.sql

@@ -0,0 +1,20 @@
+-- What the upstream answered, on the inbound journal's rows
+-- (inbound-upstream-result, 2.10.0; owner, 2026-10-16). A row of mail
+-- accepted on port 25 keeps the message's queue id, which the inbound journal
+-- milter reads at end-of-message, and starts "queued" ("held" when the filter
+-- had it held in the queue); the log tailer puts
+-- each delivery attempt's result on it - the status, the host that answered
+-- ("" when Postfix had no session), its reply and when - from the postfix/smtp
+-- line of that queue id and recipient. sent and bounced are final. A refused
+-- message has no queue id and no result, and neither has a row written before
+-- this file.
+ALTER TABLE inbound_spam_log ADD COLUMN queue_id TEXT NOT NULL DEFAULT '';
+ALTER TABLE inbound_spam_log ADD COLUMN upstream_status TEXT NOT NULL DEFAULT ''
+    CHECK (upstream_status IN ('', 'queued', 'held', 'sent', 'deferred', 'bounced'));
+ALTER TABLE inbound_spam_log ADD COLUMN upstream_relay TEXT NOT NULL DEFAULT '';
+ALTER TABLE inbound_spam_log ADD COLUMN upstream_reply TEXT NOT NULL DEFAULT '';
+ALTER TABLE inbound_spam_log ADD COLUMN upstream_at TEXT NOT NULL DEFAULT '';
+
+-- The tailer finds a row by its queue id at every delivery line; only rows
+-- of accepted mail have one.
+CREATE INDEX idx_inbound_spam_log_queue_id ON inbound_spam_log(queue_id) WHERE queue_id <> '';