Problem 3/4: Add usePermissions hook + PermissionItem/PermissionsResponse interfaces

frontend/src/api/hooks.ts

@@ -81,6 +81,19 @@ export interface Role {
   field_permissions?: Record<string, any>;
 }
 
+export interface PermissionItem {
+  key: string;
+  label: string;
+  category: string;
+  plugin_name?: string;
+}
+
+export interface PermissionsResponse {
+  system: PermissionItem[];
+  plugins: PermissionItem[];
+  all: PermissionItem[];
+}
+
 export interface Plugin {
   name: string;
   display_name?: string;
@@ -502,6 +515,13 @@ export function useRoles() {
   });
 }
 
+export function usePermissions() {
+  return useQuery({
+    queryKey: ['permissions'],
+    queryFn: () => apiGet<PermissionsResponse>('/roles/permissions'),
+  });
+}
+
 export function useCreateRole() {
   const queryClient = useQueryClient();
   return useMutation({