fix(staples): validate isStaple is boolean before forwarding to backend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/household/staples/server.test.ts

@@ -60,4 +60,18 @@ describe('household staples PATCH handler', () => {
 		expect(response.status).toBe(400);
 		expect(mockPatch).not.toHaveBeenCalled();
 	});
+
+	it('returns 400 when isStaple is missing', async () => {
+		const response = await PATCH(createRequest({ id: 'ing-1' }));
+
+		expect(response.status).toBe(400);
+		expect(mockPatch).not.toHaveBeenCalled();
+	});
+
+	it('returns 400 when isStaple is not a boolean', async () => {
+		const response = await PATCH(createRequest({ id: 'ing-1', isStaple: 'yes' }));
+
+		expect(response.status).toBe(400);
+		expect(mockPatch).not.toHaveBeenCalled();
+	});
 });