release: 1.9.0: Per-application client IP allow-list and rate-limit overrides

Application sending controls: client IP allow-list for authorization, and level-2 rate limits that override the domain ceiling per application.
Added:
  - Per-application **client IP allow-list** on the domain page: when enabled,
  - SQLite migration `0009_application_auth_ips.sql` (moves legacy trusted IPs
Changed:
  - Application level-2 rate limit **overrides** the domain limit for that login
  - Domain export/import carries `auth_ip_restrict` / `auth_allowed_ips`; legacy
  - Panel help, Settings, and [guide.md](docs/guide.md) describe override semantics
  - [guide.md](docs/guide.md): full-backup section documents all four capture

Full detail: CHANGELOG.md (1.9.0).

internal/web/handlers/handlers_apps.go

@@ -46,7 +46,7 @@ type detailView struct {
 type appRateLimitView struct {
 	store.Application
 	HasLimit       bool
-	IPsText        string
+	AuthIPsText    string
 	MaxText        string
 	WindowVal      string
 	Mode           string
@@ -116,7 +116,7 @@ func (h *Handlers) renderDomainDetail(w http.ResponseWriter, r *http.Request, st
 		appViews = append(appViews, appRateLimitView{
 			Application:    a,
 			HasLimit:       ok && rl.Active(),
-			IPsText:        strings.Join(rl.AllowedIPs, "\n"),
+			AuthIPsText:    strings.Join(a.AuthAllowedIPs, "\n"),
 			MaxText:        intOrBlank(rl.MaxMessages),
 			WindowVal:      windowOrDefault(rl.WindowSeconds),
 			Mode:           mode,
@@ -332,6 +332,8 @@ func detailFlash(r *http.Request) string {
 		return "Application address mode updated."
 	case r.URL.Query().Get("ratelimit") != "":
 		return "Rate limit updated."
+	case r.URL.Query().Get("authips") != "":
+		return "Client IP restriction updated."
 	case r.URL.Query().Get("recalculated") != "":
 		return "Auto rate limit recalculated."
 	case r.URL.Query().Get("dmarc") != "":