feat: implement WhatsApp connection and message metrics

Added tracking for all WhatsApp-related metrics:

Connection metrics:
- active_connections: Gauge tracking active connections (inc on open, dec on close)
- connection_attempts_total: Counter for connection attempts (success/failure)

Message metrics:
- messages_sent_total: Counter with type label (text, image, video, audio, etc)
- messages_received_total: Counter with type label
- history_sync_messages_total: Counter for history sync messages

Added helper functions in prometheus-metrics.ts:
- incrementActiveConnections(), decrementActiveConnections(), setActiveConnections()
- recordConnectionAttempt(status)
- recordMessageSent(type), recordMessageReceived(type)
- recordMessageRetry(type), recordMessageFailure(type, reason)
- setMessagesQueued(count, priority)
- recordHistorySyncMessages(count)

src/Utils/process-message.ts

@@ -16,7 +16,7 @@ import type {
 	WAMessage,
 	WAMessageKey
 } from '../Types'
-import { metrics } from './prometheus-metrics.js'
+import { metrics, recordHistorySyncMessages } from './prometheus-metrics.js'
 import { WAMessageStubType } from '../Types'
 import { getContentType, normalizeMessageContent } from '../Utils/messages'
 import {
@@ -353,6 +353,11 @@ const processMessage = async (
 						isLatest: histNotification.syncType !== proto.HistorySync.HistorySyncType.ON_DEMAND ? isLatest : undefined,
 						peerDataRequestSessionId: histNotification.peerDataRequestSessionId
 					})
+
+					// Record history sync metrics
+					if (data.messages?.length) {
+						recordHistorySyncMessages(data.messages.length)
+					}
 				}
 
 				break

src/Utils/prometheus-metrics.ts

@@ -1971,6 +1971,120 @@ export function updateAdaptiveMetrics(eventRate: number, isHealthy: boolean): vo
 	}
 }
 
+// ============================================
+// WhatsApp Connection & Message Metrics
+// ============================================
+
+/**
+ * Increment active connections gauge
+ */
+export function incrementActiveConnections(): void {
+	try {
+		metrics.activeConnections?.inc({})
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Decrement active connections gauge
+ */
+export function decrementActiveConnections(): void {
+	try {
+		metrics.activeConnections?.dec({})
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Set active connections to specific value
+ */
+export function setActiveConnections(count: number): void {
+	try {
+		metrics.activeConnections?.set({}, count)
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Record a connection attempt
+ */
+export function recordConnectionAttempt(status: 'success' | 'failure'): void {
+	try {
+		metrics.connectionAttempts?.inc({ status })
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Record a message sent
+ */
+export function recordMessageSent(type: string = 'text'): void {
+	try {
+		metrics.messagesSent?.inc({ type })
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Record a message received
+ */
+export function recordMessageReceived(type: string = 'text'): void {
+	try {
+		metrics.messagesReceived?.inc({ type })
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Record a message retry attempt
+ */
+export function recordMessageRetry(type: string = 'text'): void {
+	try {
+		metrics.messageRetries?.inc({ type })
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Record a message failure
+ */
+export function recordMessageFailure(type: string = 'text', reason: string = 'unknown'): void {
+	try {
+		metrics.messageFailures?.inc({ type, reason })
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Update messages queued gauge
+ */
+export function setMessagesQueued(count: number, priority: string = 'normal'): void {
+	try {
+		metrics.messagesQueued?.set({ priority }, count)
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
+/**
+ * Record history sync messages
+ */
+export function recordHistorySyncMessages(count: number = 1): void {
+	try {
+		metrics.historySyncMessages?.inc({}, count)
+	} catch {
+		// Metrics not initialized, ignore silently
+	}
+}
+
 // ============================================
 // Global Instance
 // ============================================