release: 0.5.0: Pre-1.0 security review, domain-admin role, doc consolidation

A bounce could be recorded as a successful delivery. The log-tailer's
Fixed:
  - A bounce could be recorded as a successful delivery. The log-tailer's
  - Log-tailer resumes where it stopped instead of jumping to end-of-file on
  - Level-2 rate limit no longer overshoots under concurrency: messages that
Changed:
  - The project has a single public home: `github.com/mixeme/selfpost`. Codeberg
  - Code comments no longer cite the archived specification. References like
  - `docs/code-review.md` is gone. Its plan is finished — phases 0 (bar the
  - `docs/architecture.md` gained a *Code layers* section: a diagram of
  - Phase 1 doc/code hygiene (`docs/code-review.md`): removed ~30 stale
  … (1 more in CHANGELOG)
Security:
  - Pre-release security review (plan § D, model Fable, 2026-08-06): full pass
  - `saslpasswd2` argv: the application login is now passed after a `--`
Added:
  - Optional password encryption for the two secret-bearing downloads (plan
  - Domain import accepts an encrypted export: the envelope is detected by its
  - `selfpost-backup` writes encrypted archives and reads them back:
  - `TestParseDelivery` covers the exotic mail.log shapes the review asked for
  - docs: README *Encrypting a backup or export*; `docs/security.md` §
  … (14 more in CHANGELOG)
Removed:
  - docs: `security.md` — accepted risk «restore old backup revives session rows»
Changed:
  - docs: `implementation-plan.md` trimmed to the sole open v1.x gate — pre-release
  - docs: `architecture.md` — sessions (SQLite, idle renew, password change),
  - docs: `development.md` — expanded e2e stack and `release.yml` matrix workflow.
  - docs: `security.md` — accepted risk for send-log rows stuck at `queued` after
  - docs: `roadmap.md` — optional send-log / `mail.log` follow-ups under v1.x tail.
  … (10 more in CHANGELOG)

Full detail: CHANGELOG.md (0.5.0).

internal/domain/dkim.go

@@ -1,8 +1,8 @@
 // Package domain owns SelfPost's sending-domain model: per-domain DKIM key
 // generation, the OpenDKIM KeyTable/SigningTable that drive signing, and the
 // orchestration that keeps the SQLite registry, the on-disk keys and OpenDKIM
-// in agreement (spec 4.1, 6). Key material lives under /data so it survives
-// container restarts (spec 6.1, 9).
+// in agreement (architecture.md § OpenDKIM). Key material lives under /data so
+// it survives container restarts (architecture.md § OpenDKIM).
 package domain
 
 import (
@@ -46,7 +46,7 @@ func writePrivateKeyPEM(path string, key *rsa.PrivateKey) error {
 
 // loadPrivateKeyPEM reads and parses a PKCS#1 RSA private key written by
 // writePrivateKeyPEM. It is used to recompute the public DNS record on demand,
-// keeping the private key file the single source of truth (spec 7.2.10).
+// keeping the private key file the single source of truth (product.md).
 func loadPrivateKeyPEM(path string) (*rsa.PrivateKey, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
@@ -63,7 +63,7 @@ func loadPrivateKeyPEM(path string) (*rsa.PrivateKey, error) {
 	return key, nil
 }
 
-// DKIMRecord is the DNS TXT record a user must publish for a domain (spec 7.2.10).
+// DKIMRecord is the DNS TXT record a user must publish for a domain (product.md).
 type DKIMRecord struct {
 	// Name is the record's host, e.g. "selfpost._domainkey.example.com".
 	Name string
@@ -89,7 +89,7 @@ func dkimRecord(selector, domainName string, pub *rsa.PublicKey) (DKIMRecord, er
 // writeFileAtomic writes data to path via a temp file in the same directory
 // followed by a rename, so readers only ever see the complete old or new file.
 // It is the single safe-write primitive for DKIM keys and OpenDKIM tables
-// (spec 7.6.4).
+// (security.md).
 func writeFileAtomic(path string, data []byte, perm os.FileMode) error {
 	dir := filepath.Dir(path)
 	tmp, err := os.CreateTemp(dir, ".tmp-*")