release: 1.9.2: Review pass: port-25 milters, DMARC validation, rate-limit fix

Review pass over `1.4.0`…`1.9.1`: port 25 no longer shares the submission milter chain, DMARC reports are validated before they are stored, and the auto rate limit is correct for a non-default level-1 window. Schema migration `0010` (index only). Upgrading is a tag bump.
Added:
  - SQLite migration `0010_send_log_app_login_index.sql` —
  - DMARC aggregate reports are accepted as **zip** as well as gzip or plain XML
  - e2e: `checkPort25ConfigCombinations` regenerates the Postfix configuration
Changed:
  - README hero line and a **Positioning** block in `docs/product.md` record the
Fixed:
  - The setup account's password is hashed at bcrypt cost `12` like every other
  - Login/setup rate limiter: protecting blocked buckets from eviction is now
  - `postqueue -p` output is bounded to 4 MiB (the timeout alone left the size of
  - [schema-migrations.md](docs/schema-migrations.md): the schema section was
  - postqueue reader is now time-bounded: `postqueue -p` runs under a 5-second
  … (11 more in CHANGELOG)
Changed:
  - [roadmap.md](docs/roadmap.md) now carries everything the 2026-08-19 code
  - Extracted `internal/configsafe` — the empty-value and forbidden-character
  - Build, deploy and migration comments no longer cite the archived
  - Dropped the `parseDomainRateLimitForm` / `parseAppRateLimitForm` pass-through
  - Extracted shared helpers: `internal/atomicfile` (atomic temp-write+rename) and
  … (7 more in CHANGELOG)
Removed:
  - Unused legacy asset `docs/assets/icon.png` (superseded by the four brand SVGs
  - Plan documents for already-shipped features: `domain-stats-auto-ratelimit`,

Full detail: CHANGELOG.md (1.9.2).

internal/web/auth/handlers.go

@@ -15,6 +15,13 @@ const (
 	sessionCookiePrefixed = "__Host-" + sessionCookieBase
 )
 
+// BcryptCost is the work factor for every panel password hash — the setup
+// account created here and the ones the settings and user pages write
+// (security.md). bcrypt records the cost inside the hash, so raising it only
+// affects passwords set from now on; existing hashes keep verifying at the
+// cost they were written with.
+const BcryptCost = 12
+
 func (m *Module) sessionCookie() string {
 	if m.cfg.CookieSecure {
 		return sessionCookiePrefixed
@@ -219,7 +226,7 @@ func (m *Module) submitSetup(w http.ResponseWriter, r *http.Request, token strin
 		return
 	}
 
-	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), BcryptCost)
 	if err != nil {
 		logf("panel: setup: hashing password failed: %v", err)
 		m.renderSetupForm(w, http.StatusInternalServerError, token, "Internal error. Please try again.")