fix(unified-session): address code review feedback

Fixes 3 issues identified in code review:

1. ENV VAR PRECEDENCE: Changed DEFAULT_CONNECTION_CONFIG to use
   undefined for enableUnifiedSession, allowing env var
   BAILEYS_UNIFIED_SESSION_ENABLED to take precedence.
   Priority is now: explicit config > env var > default (true)

2. SINGLE INITIALIZATION: UnifiedSessionManager is now created
   only once, after sendNode is defined. This avoids:
   - Duplicate circuit breaker instances
   - State reinitialization
   - Unnecessary overhead and logs

3. CONTINUOUS TIME SYNC: serverTimeOffset is now updated on
   every received frame that contains a 't' attribute, not just
   on CB:success. This keeps the offset accurate even during
   long-running connections.

src/Defaults/index.ts

@@ -108,7 +108,9 @@ export const DEFAULT_CONNECTION_CONFIG: SocketConfig = {
 	//             + 10 buffer slots for high-load scenarios = 50 total
 	maxSocketClientListeners: 50,
 	// Unified session telemetry (reduces detection of unofficial clients)
-	enableUnifiedSession: true
+	// NOTE: undefined means "check env var first, then default to true"
+	// This allows BAILEYS_UNIFIED_SESSION_ENABLED env var to have precedence
+	enableUnifiedSession: undefined
 }
 
 export const MEDIA_PATH_MAP: { [T in MediaType]?: string } = {

src/Socket/socket.ts

@@ -94,9 +94,16 @@ export const makeSocket = (config: SocketConfig) => {
 		queryCircuitBreaker: queryCircuitBreakerConfig,
 		connectionCircuitBreaker: connectionCircuitBreakerConfig,
 		preKeyCircuitBreaker: preKeyCircuitBreakerConfig,
-		enableUnifiedSession = shouldEnableUnifiedSession()
+		// If enableUnifiedSession is explicitly set (true/false), use it
+		// Otherwise (undefined), check env var, then default to true
+		enableUnifiedSession: enableUnifiedSessionConfig
 	} = config
 
+	// Resolve enableUnifiedSession: explicit config > env var > default (true)
+	const enableUnifiedSession = enableUnifiedSessionConfig !== undefined
+		? enableUnifiedSessionConfig
+		: shouldEnableUnifiedSession()
+
 	// Initialize circuit breakers if enabled
 	let queryCircuitBreaker: CircuitBreaker | undefined
 	let connectionCircuitBreaker: CircuitBreaker | undefined
@@ -148,18 +155,8 @@ export const makeSocket = (config: SocketConfig) => {
 		logger.info('Circuit breakers initialized for socket operations')
 	}
 
-	// Initialize Unified Session Manager for telemetry
-	// Note: sendNode will be set after it's defined below
+	// Unified Session Manager will be initialized after sendNode is defined
 	let unifiedSessionManager: UnifiedSessionManager | undefined
-	if (enableUnifiedSession) {
-		unifiedSessionManager = createUnifiedSessionManager({
-			enabled: true,
-			logger,
-			enableCircuitBreaker
-			// sendNode will be configured after sendNode function is defined
-		})
-		logger.info('Unified session manager initialized')
-	}
 
 	const publicWAMBuffer = new BinaryInfo()
 
@@ -240,19 +237,19 @@ export const makeSocket = (config: SocketConfig) => {
 		return sendRawMessage(buff)
 	}
 
-	// Configure unified session manager with sendNode now that it's defined
-	if (unifiedSessionManager) {
-		// Create a wrapper that matches the expected signature
+	// Initialize Unified Session Manager now that sendNode is defined
+	// (single initialization to avoid duplicating circuit breakers and state)
+	if (enableUnifiedSession) {
 		const sendNodeForSession = async (node: BinaryNode): Promise<void> => {
 			await sendNode(node)
 		}
-		// Recreate with proper sendNode
 		unifiedSessionManager = createUnifiedSessionManager({
 			enabled: true,
 			logger,
 			enableCircuitBreaker,
 			sendNode: sendNodeForSession
 		})
+		logger.info('Unified session manager initialized')
 	}
 
 	/** Send unified_session telemetry */
@@ -742,6 +739,13 @@ export const makeSocket = (config: SocketConfig) => {
 			if (!(frame instanceof Uint8Array)) {
 				const msgId = frame.attrs.id
 
+				// Update server time offset from any node with timestamp 't'
+				// This keeps the offset accurate even after long connections
+				const serverTime = extractServerTime(frame)
+				if (serverTime) {
+					unifiedSessionManager?.updateServerTimeOffset(serverTime)
+				}
+
 				if (logger.level === 'trace') {
 					logger.trace({ xml: binaryNodeToString(frame), msg: 'recv xml' })
 				}