fix(operator): use per-router names for VLLMRouter pod-viewer RBAC

[Anai-Guo]

What

VLLMRouter reconciliation creates a Role and RoleBinding (granting get/list/watch on pods) using fixed names pod-viewer-role / pod-viewer-binding, both owner-referenced to the creating router. This makes it impossible to run more than one VLLMRouter in the same namespace (#900):

• The second router finds the existing RoleBinding (creation is skipped) whose only subject is the first router's ServiceAccount — so the second router's SA is never bound and its pods cannot list pods.
• Because the shared Role/RoleBinding are owned by the router that first created them, deleting that router garbage-collects them, breaking the surviving router.

Change

Derive both RBAC object names from the router name via two small helpers:

func podViewerRoleName(router *servingv1alpha1.VLLMRouter) string {
    return fmt.Sprintf("%s-pod-viewer-role", router.Name)
}
func podViewerBindingName(router *servingv1alpha1.VLLMRouter) string {
    return fmt.Sprintf("%s-pod-viewer-binding", router.Name)
}

Each router now gets its own Role and RoleBinding bound to its own ServiceAccount, so multiple routers coexist in one namespace and lifecycle events on one no longer affect the others. The RoleRef in the binding is updated to point at the per-router role name.

No behavior change for single-router namespaces (name is just prefixed). fmt is already imported; no test references the old fixed names.

Fixes #900

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request updates the VLLM router controller to use dynamic, per-router names for the RBAC Role and RoleBinding instead of static names, allowing multiple VLLMRouters to coexist in the same namespace. The feedback suggests adding nil checks for the router parameter in the helper functions podViewerRoleName and podViewerBindingName to prevent potential nil pointer dereferences.

[gemini-code-assist]

For defensive programming, we should ensure that router is not nil before accessing its fields to prevent potential nil pointer dereference panics.

Suggested change

	func podViewerRoleName(router *servingv1alpha1.VLLMRouter) string {
	return fmt.Sprintf("%s-pod-viewer-role", router.Name)
	}
	func podViewerRoleName(router *servingv1alpha1.VLLMRouter) string {
	if router == nil {
	return ""
	}
	return fmt.Sprintf("%s-pod-viewer-role", router.Name)
	}

[gemini-code-assist]

For defensive programming, we should ensure that router is not nil before accessing its fields to prevent potential nil pointer dereference panics.

func podViewerBindingName(router *servingv1alpha1.VLLMRouter) string {
	if router == nil {
		return ""
	}
	return fmt.Sprintf("%s-pod-viewer-binding", router.Name)
}