Finish fine-grained ACL across remaining admin pages and actions.

Replace leftover requireStaff gates with module PERMS, drop hardcoded room rank thresholds, and expand contract tests so admin mutations cannot regress to dashboard-only checks.

Co-authored-by: Cursor <[email protected]>

src/actions/admin-applications.ts

@@ -1,12 +1,13 @@
 "use server";
 
 import { revalidatePath } from "next/cache";
-import { requireStaff } from "@/lib/admin/guard";
+import { requirePermission } from "@/lib/admin/guard";
+import { PERMS } from "@/lib/permissions";
 import { formPositiveBigInt } from "@/lib/form-data";
 import { prisma } from "@/lib/prisma";
 
 export async function dismissApplication(formData: FormData): Promise<void> {
-	await requireStaff();
+	await requirePermission(PERMS.USERS_EDIT);
 	const id = formPositiveBigInt(formData, "id");
 	if (!id) return;