fix(api): increase RateLimitSelectCondition.headers MaxItems from 16 to 64

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: wucm667

api/v1alpha1/ratelimit_types.go

@@ -228,7 +228,9 @@ type RateLimitSelectCondition struct {
 	// meaning, a request MUST match all the specified headers.
 	//
 	// +optional
-	// +kubebuilder:validation:MaxItems=16
+	// +kubebuilder:validation:MaxItems=64
+	// Increase the maxItems from 16 to 64, aligning with HTTPHeaderFilter.
+	// Revert this change once the upstream Gateway API supports items more than 64.
 	Headers []HeaderMatch `json:"headers,omitempty"`
 
 	// Methods is a list of request methods to match. Multiple method values are ORed together,