feat: admin user management (create/search/role) and cluster resource monitoring

- Add POST /users endpoint for admin to create users with hashed passwords
- Add GET /users?search= with ILike search on email/firstName/lastName
- Add PATCH /users/:id/role for role assignment (user/admin)
- Return appCount per user in the users list
- Add GET /clusters/:id/resources for node, CPU, memory, pod monitoring
- Parse K8s node capacity/allocatable with CPU millicores and memory MiB helpers
- Frontend: admin users page with search bar, create form, role dropdown, app count
- Frontend: cluster resource panel with nodes table, CPU/memory bars, summary cards

frontend/src/types/index.ts

@@ -156,3 +156,28 @@ export interface ResourceUsage {
   pods: PodInfo[];
   metrics: PodMetric[];
 }
+
+export interface AdminUser extends User {
+  appCount?: number;
+}
+
+export interface ClusterNode {
+  name: string;
+  status: string;
+  roles: string;
+  cpuCapacity: string;
+  memoryCapacity: string;
+  cpuAllocatable: string;
+  memoryAllocatable: string;
+}
+
+export interface ClusterResources {
+  nodes: ClusterNode[];
+  totalCpuCapacity: string;
+  totalMemoryCapacity: string;
+  totalCpuAllocatable: string;
+  totalMemoryAllocatable: string;
+  podCount: number;
+  nodeCount: number;
+  appCount: number;
+}