release: 1.3.0: 1.3.0-1.3.1: security pass, queue persist, full backup layout

[1.3.0]
Security and quality after 1.2.5: domain-admin send-log authorization, fail-closed sign-in and application delete, level-2 rate-limit race fix, restore Resync, expanded tests, operator docs, release CI, and OFL for IBM Plex. Upgrading from 1.2.x is a tag bump; no migration.
Added:
  - licence: the SIL Open Font License 1.1 text now travels with the IBM Plex
  - docs: agreed roadmap item **queue-retries** — show this Postfix's retry
Security:
  - The independent security review of the send-log authorization and
Fixed:
  - test (e2e): send-log status scrapers follow the badge markup in
  - security (panel): the Deliveries list is scoped to a domain administrator's
  - mail (level-2 rate limit): the ceiling is no longer overshot by messages that
  - panel (sign-in): a session that cannot be written to the database no longer
  - panel (applications): deleting an application removes its SASL credentials
  … (2 more in CHANGELOG)
Changed:
  - docs: operator and as-built docs aligned with the code after a full
  - docs: [guide.md](docs/guide.md) reorganised into **Installation**, **Instance
  - docs: the 2026-08-13 full-tree review plan is complete — every phase (P0–P7)
  - licence: [NOTICE](NOTICE) tells modifiers to update `SourceURL` in
  - ci: the release image is published only for a **published** GitHub Release
  … (9 more in CHANGELOG)
[1.3.1]
Retry policy in the panel, persistent Postfix queue, and self-contained full backups. Mail queue and delivery history show this Postfix's first retry, backoff cap, and queue lifetime. Deferred mail survives container recreate. Full backups now archive `data/`, compose, `.env`, and `certs/`; the archive layout breaks 1.3.0 flat backups (unpack those with `tar xzf backup.tar.gz -C ./data` as before). Upgrading from 1.3.0 is a tag bump; no schema migration.
Added:
  - Mail queue and a delivery's history show this Postfix's retry policy
  - docs: **Plan checklists** in [development.md](docs/development.md) — format,
  - docs: **Implementation checklists** with model routing in
  - docs: roadmap candidates **send-log-retention** (panel Settings for delivery
  - Postfix queue under `/data/postfix/queue` — deferred and active mail survive
  … (1 more in CHANGELOG)
Changed:
  - **Breaking:** full-backup archive layout — paths are prefixed with `data/`;
  - docs: operator guide, architecture, security, and backup UI updated for
  - docs: HTML mockups for a full panel UI refresh
Changed:
  - docs: panel UI mockups after review — Status restored to live readings
  - docs: panel UI design system and mockups rebuilt as separate pages
  - docs: panel UI mockups — add-domain sits in the list card (Domains and
Fixed:
  - ci (GHCR): per-arch package tags (`X.Y.Z-amd64`, `X.Y.Z-arm64`) are dropped

Squashed CHANGELOG sections: [1.3.0], [1.3.1].

Full detail: CHANGELOG.md (1.3.0, 1.3.1).

internal/milter/ratelimit.go

@@ -54,22 +54,23 @@ func (s *session) overLimit() bool {
 }
 
 // enforceLimit counts recent messages for scope/ref and refuses when at or
-// above the ceiling. On admit it reserves an in-flight slot on the session.
+// above the ceiling. The stored count and the in-flight slots are weighed and
+// the admitted message's own slot is taken in one atomic step (tryAdmit), so
+// two sessions racing at MAIL FROM cannot both claim the last free slot.
 func (s *session) enforceLimit(scope, ref string, rl store.RateLimit) bool {
 	since := time.Now().Add(-time.Duration(rl.WindowSeconds) * time.Second)
-	n, err := s.rec.CountMessages(scope, ref, since)
+	stored, err := s.rec.CountMessages(scope, ref, since)
 	if err != nil {
 		log.Printf("journal-milter: rate-limit count %s %q: %v (fail-open)", scope, ref, err)
 		return false
 	}
-	key := scope + "|" + ref
-	n += s.flight.count(key, since)
-	if n >= int64(rl.MaxMessages) {
+	r, n, ok := s.flight.tryAdmit(scope+"|"+ref, since, stored, int64(rl.MaxMessages))
+	if !ok {
 		log.Printf("journal-milter: %s %q over limit: %d/%d in %ds from %s — refusing 4xx",
 			scope, ref, n, rl.MaxMessages, rl.WindowSeconds, s.clientIP)
 		return true
 	}
-	s.reserved = append(s.reserved, s.flight.reserve(key))
+	s.reserved = append(s.reserved, r)
 	return false
 }