feat: Implement comprehensive multi-channel notification system with templating and SSL monitoring

- Add robust notification system supporting 7+ communication channels with intelligent message templating, resource monitoring, and SSL certificate alerts. Notification Channels: (Telegram, Discord, Slack, Signal, Email, Google Chat, Webhooks).

- This notification system provides enterprise-grade alerting capabilities with extensive customization options and multi-channel redundancy for critical service monitoring.

server/service-operation/ssl-monitoring/monitor.go

@@ -0,0 +1,98 @@
+
+package sslmonitoring
+
+import (
+	"time"
+
+	"service-operation/pocketbase"
+)
+
+// SSLMonitor monitors SSL certificates and sends notifications
+type SSLMonitor struct {
+	client              *SSLClient
+	notificationService *SSLNotificationService
+	checkInterval       time.Duration
+	stopChan            chan bool
+}
+
+// NewSSLMonitor creates a new SSL monitor
+func NewSSLMonitor(pbClient *pocketbase.PocketBaseClient) *SSLMonitor {
+	// Initialize SSL client
+	sslClient := NewSSLClient(pbClient)
+	
+	// Initialize notification service
+	notificationService := NewSSLNotificationService(sslClient, pbClient)
+
+	// Set check interval to 30 seconds to match other services
+	checkInterval := 30 * time.Second
+
+	return &SSLMonitor{
+		client:              sslClient,
+		notificationService: notificationService,
+		checkInterval:       checkInterval,
+		stopChan:            make(chan bool, 1),
+	}
+}
+
+// Start begins monitoring SSL certificates
+func (sm *SSLMonitor) Start() {
+	// log.Printf("🚀 [SSL-MONITOR] Starting with check interval: %v", sm.checkInterval)
+	// log.Printf("⏰ [SSL-MONITOR] Startup grace period: 2 minutes (no notifications for valid certificates)")
+
+	// Run initial check
+	sm.checkCertificates()
+
+	// Set up periodic checking every 30 seconds
+	ticker := time.NewTicker(sm.checkInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			sm.checkCertificates()
+		case <-sm.stopChan:
+			// log.Println("🛑 [SSL-MONITOR] Monitoring stopped")
+			return
+		}
+	}
+}
+
+// Stop gracefully stops the SSL monitoring
+func (sm *SSLMonitor) Stop() {
+	// log.Printf("🛑 [SSL-MONITOR] Stopping SSL monitoring...")
+	select {
+	case sm.stopChan <- true:
+	default:
+	}
+}
+
+// checkCertificates fetches all SSL certificates and checks their notification requirements
+func (sm *SSLMonitor) checkCertificates() {
+	// log.Printf("🔍 [SSL-CHECK] Checking SSL certificates for expiration alerts...")
+
+	certificates, err := sm.client.GetSSLCertificates()
+	if err != nil {
+		// log.Printf("❌ [SSL-ERROR] Failed to fetch SSL certificates: %v", err)
+		return
+	}
+
+	// log.Printf("📊 [SSL-CERTIFICATES] Found %d certificates to check", len(certificates))
+
+	successCount := 0
+	errorCount := 0
+
+	for _, cert := range certificates {
+		// Check each certificate for notification requirements
+		if err := sm.notificationService.CheckAndNotifySSLCertificate(cert); err != nil {
+			// log.Printf("❌ [SSL-FAILED] Failed to process certificate %s: %v", cert.Domain, err)
+			errorCount++
+		} else {
+			successCount++
+		}
+	}
+
+	// log.Printf("✅ [SSL-SUMMARY] Processed %d certificates (success: %d, errors: %d)", 
+	//	len(certificates), successCount, errorCount)
+	_ = successCount // Prevent unused variable warning
+	_ = errorCount   // Prevent unused variable warning
+}