fix(grpc/client): wait for full reconnection readiness before clearing reconnecting flag

- add maxReconnectionWait and reconnectionCheckInterval constants for reconnection readiness polling
- introduce waitForFullReconnectionReady() to verify: connection READY, clients registered, and ability to obtain critical service clients (model/task) within short timeouts
- ensure reconnecting flag is cleared immediately on reconnection failure and only cleared after full readiness checks on success
- improve logging around reconnection stabilization and readiness checks

core/grpc/client/client.go

@@ -31,6 +31,8 @@ const (
 	defaultClientTimeout         = 15 * time.Second // Increased from 5s for better reconnection handling
 	reconnectionClientTimeout    = 90 * time.Second // Extended timeout during reconnection scenarios (must be > worker reset timeout)
 	connectionStabilizationDelay = 2 * time.Second  // Wait after reconnection before declaring success
+	maxReconnectionWait          = 30 * time.Second // Maximum time to wait for full reconnection completion
+	reconnectionCheckInterval    = 500 * time.Millisecond
 )
 
 // Circuit breaker states
@@ -806,11 +808,8 @@ func (c *GrpcClient) executeReconnection() {
 	c.reconnecting = true
 	c.reconnectMux.Unlock()
 
-	defer func() {
-		c.reconnectMux.Lock()
-		c.reconnecting = false
-		c.reconnectMux.Unlock()
-	}()
+	// Don't use defer to clear reconnecting flag - we need to control the timing precisely
+	// to ensure all dependent services have completed registration before clearing it
 
 	c.Infof("executing reconnection to %s (current state: %s)", c.address, c.getState())
 
@@ -818,6 +817,11 @@ func (c *GrpcClient) executeReconnection() {
 		c.Errorf("reconnection failed: %v", err)
 		c.recordFailure()
 
+		// Clear reconnecting flag on failure
+		c.reconnectMux.Lock()
+		c.reconnecting = false
+		c.reconnectMux.Unlock()
+
 		// Exponential backoff before allowing next attempt
 		backoffDuration := c.calculateBackoff()
 		c.Warnf("will retry reconnection after %v backoff", backoffDuration)
@@ -837,9 +841,80 @@ func (c *GrpcClient) executeReconnection() {
 		} else {
 			c.Warnf("connection became unstable during stabilization")
 		}
+
+		// Wait for full registration and service readiness before clearing reconnecting flag
+		// This ensures all dependent services can successfully get their clients with extended timeout
+		if c.waitForFullReconnectionReady() {
+			c.Infof("reconnection fully complete, all services ready")
+		} else {
+			c.Warnf("reconnection completed but some checks didn't pass within timeout")
+		}
+
+		// Now it's safe to clear the reconnecting flag
+		c.reconnectMux.Lock()
+		c.reconnecting = false
+		c.reconnectMux.Unlock()
+		c.Infof("resuming normal operation mode")
 	}
 }
 
+// waitForFullReconnectionReady waits for the client to be fully ready after reconnection
+// by verifying all critical service clients can be successfully obtained.
+// This ensures dependent services won't fail with "context cancelled" errors.
+func (c *GrpcClient) waitForFullReconnectionReady() bool {
+	c.Debugf("waiting for full reconnection readiness (max %v)", maxReconnectionWait)
+	startTime := time.Now()
+	checkCount := 0
+
+	for time.Since(startTime) < maxReconnectionWait {
+		checkCount++
+
+		// Check 1: Connection must be in READY state
+		if c.conn == nil || c.conn.GetState() != connectivity.Ready {
+			c.Debugf("check %d: connection not ready (state: %v)", checkCount, c.getState())
+			time.Sleep(reconnectionCheckInterval)
+			continue
+		}
+
+		// Check 2: Client must be registered
+		if !c.IsRegistered() {
+			c.Debugf("check %d: client not yet registered", checkCount)
+			time.Sleep(reconnectionCheckInterval)
+			continue
+		}
+
+		// Check 3: Verify we can actually get service clients without timeout
+		// This is the critical check that ensures dependent services won't fail
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+
+		// Try to get model base service client (most commonly used by TaskHandler)
+		_, err1 := c.GetModelBaseServiceClientWithContext(ctx)
+
+		// Try to get task client (used for task operations)
+		_, err2 := c.GetTaskClientWithContext(ctx)
+
+		cancel()
+
+		if err1 != nil || err2 != nil {
+			c.Debugf("check %d: service clients not ready (model: %v, task: %v)",
+				checkCount, err1, err2)
+			time.Sleep(reconnectionCheckInterval)
+			continue
+		}
+
+		// All checks passed!
+		elapsed := time.Since(startTime)
+		c.Infof("full reconnection readiness achieved after %v (%d checks)", elapsed, checkCount)
+		return true
+	}
+
+	// Timeout reached
+	elapsed := time.Since(startTime)
+	c.Warnf("reconnection readiness checks did not complete within %v (elapsed: %v, checks: %d)",
+		maxReconnectionWait, elapsed, checkCount)
+	return false
+}
+
 // Enhanced circuit breaker methods
 func (c *GrpcClient) getCircuitBreakerState() circuitBreakerState {
 	c.cbMux.RLock()