refactor: remove standalone proxies, add Traefik provider with Docker labels

Standalone proxy removal:
- Delete store, API handlers, proxy manager, health monitor, validator, hints
- Delete frontend pages (proxies list, create, edit) and components (ProxyCard, ProxyForm, ProxyFilter, ProxyGroup, ValidationChecklist)
- Remove proxy routes from router, nav items, dashboard references
- Clean up SystemHealthCard to remove proxy section

Traefik provider:
- Add TraefikProvider implementing proxy.Provider via Docker labels
- ContainerLabels() returns traefik.enable, router rule, entrypoints, service port, TLS cert resolver, docker network
- ConfigureRoute() returns router name (labels handle routing at container creation)
- DeleteRoute() is no-op (container removal auto-deregisters)
- Ping() checks Traefik API health (optional)
- Wire ContainerLabels into deployer (executeDeploy + blueGreenDeploy)
- Add Traefik settings: entrypoint, cert_resolver, network, api_url
- Add traefik option to proxy provider selector in settings UI
- Show conditional Traefik config fields
- Add i18n keys (EN + RU)

cmd/server/main.go

@@ -101,6 +101,14 @@ func main() {
 	case "none":
 		proxyProvider = proxy.NewNoneProvider()
 		slog.Info("proxy provider: none")
+	case "traefik":
+		proxyProvider = proxy.NewTraefikProvider(
+			settings.TraefikEntrypoint,
+			settings.TraefikCertResolver,
+			settings.TraefikNetwork,
+			settings.TraefikAPIURL,
+		)
+		slog.Info("proxy provider: traefik", "entrypoint", settings.TraefikEntrypoint)
 	default:
 		// Default to NPM for backward compatibility (including "npm" and empty string).
 		npmPassword := ""
@@ -164,13 +172,6 @@ func main() {
 		slog.Warn("failed to start stale scanner", "error", err)
 	}
 
-	// Initialize proxy manager and health monitor.
-	proxyManager := proxy.NewManager(db, proxyProvider)
-	proxyHealth := proxy.NewHealthMonitor(db, eventBus)
-	if err := proxyHealth.Start("5m"); err != nil {
-		slog.Warn("failed to start proxy health monitor", "error", err)
-	}
-
 	// Start daily event log pruning cron job.
 	cronScheduler := cron.New()
 	if _, err := cronScheduler.AddFunc("@daily", func() {
@@ -220,7 +221,6 @@ func main() {
 	dnsProvider := initDNSProvider(settings, encKey)
 	if dnsProvider != nil {
 		dep.SetDNSProvider(dnsProvider)
-		proxyManager.SetDNSProvider(dnsProvider)
 		slog.Info("DNS provider initialized", "provider", settings.DNSProvider)
 	}
 
@@ -283,14 +283,12 @@ func main() {
 	// Build API server.
 	apiServer := api.NewServer(db, dockerClient, npmClient, proxyProvider, dep, webhookHandler, eventBus, encKey)
 	apiServer.SetStaleScanner(staleScanner)
-	apiServer.SetProxyManager(proxyManager)
 	apiServer.SetBackupEngine(backupEngine)
 	apiServer.SetDBPath(dbPath)
 	apiServer.SetBackupSettingsChangedCallback(scheduleAutobackup)
 	apiServer.SetDNSProvider(dnsProvider)
 	apiServer.SetDNSProviderChangedCallback(func(provider dns.Provider) {
 		dep.SetDNSProvider(provider)
-		proxyManager.SetDNSProvider(provider)
 	})
 	router := apiServer.Router()
 
@@ -340,7 +338,6 @@ func main() {
 	// Stop accepting new work.
 	cronScheduler.Stop()
 	eventBus.Unsubscribe(notifySub)
-	proxyHealth.Stop()
 	staleScanner.Stop()
 	poller.Stop()