audit 6: documents, comments, dead code and staticcheck; the test gaps closed

The last stage of the 2026-10-12 audit; no cut.

Doc drift: architecture.md (the sender check in § OpenDKIM, the limit:
row's 48 hours, the inbound log and filter-list routes and who may open
them, migrations to 0011 and every table, KitPage as production data,
Reload configuration as a restore writes, the panel's roles counted),
schema-migrations.md (tables and columns since v2), guide.md (a delivery's
lines go at the next prune; INBOUND_JOURNAL_MILTER_SOCKET moved to
architecture.md's internal list), development.md (the env guard, the
deferral the e2e proves, its fixed sleeps), roadmap.md.

Comments say what the code does now; TestBaselineIsTheOnlyMigration is
TestChainStartsAtTheBaseline; the milter package doc names its three
milters.

Dead code gone: view.Facts, dmarc HostedSuggestion and
ValidateHostedAddress, app UpdateMode (each with the test that alone kept
it), the method checks the method-bound routes made dead;
Settings.WithResult calls resultFlash. staticcheck 2026.1 in test.yml on
both modules, clean: the e2e package builds without its tests now (a test
and two constants moved out of non-test files), three findings fixed.
The test moved, TestImageBuildPreservesLogrotateMode, had sat in a
non-test file and never run; run, it failed on the entrypoint (docker run
without a hostname) and now asks with --entrypoint stat.

The test gaps no step named, each closed: follow() with mail.log gone past
blindMin and made again; CheckRestore with a manifest that is not JSON;
the origin check with a port; every /server/ pattern in web.go through
server() and in the routes table (it found GET /server/health/fragment
missing from the table - guarded, not tested); L9 as the owner decided it
on 2026-10-12, the comment on senderSession.Headers and the test passing
an h that holds the earlier messages' From:.

Plan stage 6 ticked; roadmap audit row done, 81/81.

Tested on the test server: go vet + go test of 27 packages, make e2e (all
pass, 513 s) on this tree; staticcheck locally on both modules.

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

test/e2e/sasldb_test.go

@@ -23,7 +23,7 @@ import (
 // mode and group stay) and that nothing fails under the load; it cannot prove
 // a race absent.
 func testSASLDBChangedByRename(t *testing.T, sc *scenario) {
-	churnLogin, churnPassword, err := sc.panel.addApplication(sc.domainID, "churn", "wildcard", "")
+	churnLogin, _, err := sc.panel.addApplication(sc.domainID, "churn", "wildcard", "")
 	if err != nil {
 		t.Fatalf("add application: %v", err)
 	}
@@ -55,6 +55,7 @@ func testSASLDBChangedByRename(t *testing.T, sc *scenario) {
 	// while the old file still exists, so it cannot have the old file's
 	// number. (After many changes it may: a freed inode number is reused.)
 	before := strings.Fields(stat())
+	var churnPassword string
 	if churnPassword, err = newPassword(0); err != nil {
 		t.Fatal(err)
 	}