fix: correct MaxSurge default assignment in SetDefaultDeploymentStrategy

The default value for MaxSurge was incorrectly assigned to
MaxUnavailable, causing MaxSurge to remain nil when not explicitly set.
This could lead to unexpected behavior in the rolling update strategy
where maxSurge==0 fallback logic would always trigger.

Made-with: Cursor

Author: Xio-Shark

api/v1beta1/deployment_types.go

@@ -100,7 +100,7 @@ func SetDefaultDeploymentStrategy(strategy *DeploymentStrategy) {
 	if strategy.RollingUpdate.MaxSurge == nil {
 		// Set MaxSurge as 25% by default
 		maxSurge := intstr.FromString("25%")
-		strategy.RollingUpdate.MaxUnavailable = &maxSurge
+		strategy.RollingUpdate.MaxSurge = &maxSurge
 	}
 
 	// Cannot allow maxSurge==0 && MaxUnavailable==0, otherwise, no pod can be updated when rolling update.