fix(operator): use per-router names for VLLMRouter pod-viewer RBAC (#993)

The Role "pod-viewer-role" and RoleBinding "pod-viewer-binding" created
for a VLLMRouter used fixed names and were owner-referenced to the
creating router. With two VLLMRouters in the same namespace this breaks:

- the second router reuses the existing RoleBinding (creation is skipped),
  so its ServiceAccount is never bound and its pods cannot list pods;
- deleting either router garbage-collects the shared Role/RoleBinding,
  breaking the surviving router.

Derive both names from the router name so each router gets its own Role
and RoleBinding bound to its own ServiceAccount.

Fixes #900

Signed-off-by: Anai-Guo <antai12232931@anaiguo.com>
Co-authored-by: Anai-Guo <antai12232931@anaiguo.com>