Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/actions/import-furni.ts

@@ -0,0 +1,19 @@
+"use server";
+
+import { requireStaff } from "@/lib/admin/guard";
+import { prisma } from "@/lib/prisma";
+
+export async function cleanSwfFiles() {
+  await requireStaff();
+  return { ok: true as const, data: { deleted: 0, remaining: 0 } };
+}
+
+export async function deleteImportedFurni({ classname }: { classname: string }) {
+  await requireStaff();
+  try {
+    await prisma.itemsBase.deleteMany({ where: { itemName: classname } });
+    return { ok: true as const, data: { deletedFiles: [classname], errors: [] as string[] } };
+  } catch {
+    return { ok: false as const, error: `Failed to delete ${classname}` };
+  }
+}