Phase 2: monitoring warnings, dashboard alerts & notification system

- Monitoring page: "Távoli monitoring" section showing healthcheck ping UUID
  configuration status (configured/not configured) for each of the 5 pings
- Alert manager: persistent dashboard banners on all pages generated from
  health check results, missing pings, and backup status
- Notification system: controller-side notifier sends events to hub relay,
  with cooldown tracking and event-type filtering
- Notification preferences UI: email, event checkboxes, cooldown settings
  on the settings page with test email functionality
- Settings refactored: shared settingsData() helper, NotificationPrefs
  struct with getter/setter and defaults

New files:
- controller/internal/web/alerts.go (AlertManager)
- controller/internal/notify/notifier.go (hub notification client)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/handlers.go

@@ -4,15 +4,17 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
+	"strings"
 
 	"gitea.dooplex.hu/admin/felhom-controller/internal/scheduler"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/system"
 	"golang.org/x/crypto/bcrypt"
 )
 
 func (s *Server) baseData(page, title string) map[string]interface{} {
-	return map[string]interface{}{
+	data := map[string]interface{}{
 		"Page":         page,
 		"Title":        title,
 		"CustomerName": s.cfg.Customer.Name,
@@ -20,6 +22,10 @@ func (s *Server) baseData(page, title string) map[string]interface{} {
 		"Version":      s.version,
 		"AuthEnabled":  s.authEnabled(),
 	}
+	if s.alertManager != nil {
+		data["Alerts"] = s.alertManager.GetAlerts()
+	}
+	return data
 }
 
 func (s *Server) dashboardHandler(w http.ResponseWriter, _ *http.Request) {
@@ -196,9 +202,41 @@ func (s *Server) appDetailHandler(w http.ResponseWriter, r *http.Request, slug s
 func (s *Server) monitoringHandler(w http.ResponseWriter, _ *http.Request) {
 	data := s.baseData("monitoring", "Rendszermonitor")
 	data["SystemInfo"] = system.GetInfo(s.cfg.Paths.HDDPath, s.cpuCollector)
+
+	// On monitoring page, exclude the "pings-missing" alert since the detailed table is visible
+	if s.alertManager != nil {
+		data["Alerts"] = s.alertManager.GetAlerts("pings-missing")
+	}
+
+	// Ping status section
+	data["MonitoringEnabled"] = s.cfg.Monitoring.Enabled
+	if s.cfg.Monitoring.Enabled {
+		pings := []map[string]interface{}{
+			{"Label": "Életjel (Heartbeat)", "Icon": "💓", "Configured": isPingConfigured(s.cfg.Monitoring.PingUUIDs.Heartbeat), "Schedule": "5 percenként"},
+			{"Label": "Rendszer állapot", "Icon": "🖥️", "Configured": isPingConfigured(s.cfg.Monitoring.PingUUIDs.SystemHealth), "Schedule": "5 percenként"},
+			{"Label": "Adatbázis mentés", "Icon": "🗄️", "Configured": isPingConfigured(s.cfg.Monitoring.PingUUIDs.DBDump), "Schedule": "Naponta " + s.cfg.Backup.DBDumpSchedule},
+			{"Label": "Biztonsági mentés", "Icon": "💾", "Configured": isPingConfigured(s.cfg.Monitoring.PingUUIDs.Backup), "Schedule": "Naponta " + s.cfg.Backup.ResticSchedule},
+			{"Label": "Mentés integritás", "Icon": "🔍", "Configured": isPingConfigured(s.cfg.Monitoring.PingUUIDs.BackupIntegrity), "Schedule": "Hetente (vasárnap)"},
+		}
+		allConfigured := true
+		for _, p := range pings {
+			if !p["Configured"].(bool) {
+				allConfigured = false
+				break
+			}
+		}
+		data["PingStatus"] = pings
+		data["AllPingsConfigured"] = allConfigured
+	}
+
 	s.render(w, "monitoring", data)
 }
 
+// isPingConfigured returns true if a healthcheck ping UUID is non-empty and not a placeholder.
+func isPingConfigured(uuid string) bool {
+	return uuid != "" && !strings.HasPrefix(uuid, "CHANGEME")
+}
+
 func (s *Server) backupsHandler(w http.ResponseWriter, _ *http.Request) {
 	data := s.baseData("backups", "Biztonsági mentés")
 
@@ -214,10 +252,8 @@ func (s *Server) backupsHandler(w http.ResponseWriter, _ *http.Request) {
 	s.render(w, "backups", data)
 }
 
-func (s *Server) settingsHandler(w http.ResponseWriter, _ *http.Request) {
+func (s *Server) settingsData() map[string]interface{} {
 	data := s.baseData("settings", "Beállítások")
-
-	// System configuration (read-only display from controller.yaml)
 	data["CustomerID"] = s.cfg.Customer.ID
 	data["CustomerDomain"] = s.cfg.Customer.Domain
 	data["GitRepoURL"] = s.cfg.Git.RepoURL
@@ -228,8 +264,12 @@ func (s *Server) settingsHandler(w http.ResponseWriter, _ *http.Request) {
 	data["MonitoringEnabled"] = s.cfg.Monitoring.Enabled
 	data["HealthchecksBase"] = s.cfg.Monitoring.HealthchecksBase
 	data["HubEnabled"] = s.cfg.Hub.Enabled
+	data["NotificationPrefs"] = s.settings.GetNotificationPrefs()
+	return data
+}
 
-	s.render(w, "settings", data)
+func (s *Server) settingsHandler(w http.ResponseWriter, _ *http.Request) {
+	s.render(w, "settings", s.settingsData())
 }
 
 func (s *Server) settingsPasswordHandler(w http.ResponseWriter, r *http.Request) {
@@ -238,17 +278,7 @@ func (s *Server) settingsPasswordHandler(w http.ResponseWriter, r *http.Request)
 	newPassword := r.FormValue("new_password")
 	confirmPassword := r.FormValue("confirm_password")
 
-	data := s.baseData("settings", "Beállítások")
-	data["CustomerID"] = s.cfg.Customer.ID
-	data["CustomerDomain"] = s.cfg.Customer.Domain
-	data["GitRepoURL"] = s.cfg.Git.RepoURL
-	data["GitSyncInterval"] = s.cfg.Git.SyncInterval
-	data["BackupEnabled"] = s.cfg.Backup.Enabled
-	data["DBDumpSchedule"] = s.cfg.Backup.DBDumpSchedule
-	data["ResticSchedule"] = s.cfg.Backup.ResticSchedule
-	data["MonitoringEnabled"] = s.cfg.Monitoring.Enabled
-	data["HealthchecksBase"] = s.cfg.Monitoring.HealthchecksBase
-	data["HubEnabled"] = s.cfg.Hub.Enabled
+	data := s.settingsData()
 
 	// Validate current password
 	effectiveHash := s.effectivePasswordHash()
@@ -298,3 +328,71 @@ func (s *Server) settingsPasswordHandler(w http.ResponseWriter, r *http.Request)
 	flash := url.QueryEscape("Jelszó sikeresen módosítva. Kérjük, jelentkezzen be az új jelszóval.")
 	http.Redirect(w, r, "/login?flash="+flash, http.StatusFound)
 }
+
+func (s *Server) settingsNotificationsHandler(w http.ResponseWriter, r *http.Request) {
+	_ = r.ParseForm()
+
+	email := strings.TrimSpace(r.FormValue("notification_email"))
+	cooldownStr := r.FormValue("cooldown_hours")
+	cooldownHours := 6
+	if cooldownStr != "" {
+		if n, err := fmt.Sscanf(cooldownStr, "%d", &cooldownHours); n != 1 || err != nil {
+			cooldownHours = 6
+		}
+	}
+	if cooldownHours < 1 {
+		cooldownHours = 1
+	}
+	if cooldownHours > 168 {
+		cooldownHours = 168
+	}
+
+	// Collect enabled events from checkboxes
+	var enabledEvents []string
+	for _, evt := range []string{"disk_warning", "backup_failed", "update_available", "security_update"} {
+		if r.FormValue("event_"+evt) == "on" {
+			enabledEvents = append(enabledEvents, evt)
+		}
+	}
+
+	prefs := &settings.NotificationPrefs{
+		Email:         email,
+		EnabledEvents: enabledEvents,
+		CooldownHours: cooldownHours,
+	}
+
+	if err := s.settings.SetNotificationPrefs(prefs); err != nil {
+		s.logger.Printf("[ERROR] Failed to save notification prefs: %v", err)
+		data := s.settingsData()
+		data["NotificationError"] = "Hiba a beállítások mentésekor"
+		s.render(w, "settings", data)
+		return
+	}
+
+	s.logger.Printf("[INFO] Notification preferences updated: email=%s, events=%v", email, enabledEvents)
+
+	data := s.settingsData()
+	data["NotificationSuccess"] = "Értesítési beállítások mentve."
+	s.render(w, "settings", data)
+}
+
+func (s *Server) settingsNotificationsTestHandler(w http.ResponseWriter, r *http.Request) {
+	data := s.settingsData()
+
+	if s.notifier == nil {
+		data["NotificationError"] = "Az értesítések nincsenek bekapcsolva"
+		s.render(w, "settings", data)
+		return
+	}
+
+	err := s.notifier.SendTest()
+	if err != nil {
+		s.logger.Printf("[ERROR] Test notification failed: %v", err)
+		data["NotificationError"] = fmt.Sprintf("Teszt email küldése sikertelen: %v", err)
+		s.render(w, "settings", data)
+		return
+	}
+
+	data["NotificationSuccess"] = "Teszt email elküldve."
+	s.render(w, "settings", data)
+}