feat(ai-character): Mock Preview 모드 구현

src/shared/api/__tests__/client.test.ts

@@ -114,4 +114,21 @@ describe("API client", () => {
     // Then
     await expect(request).rejects.toBeInstanceOf(ApiError);
   });
+
+  test("surfaces a network failure without a mock response", async () => {
+    // Given
+    vi.stubEnv("VITE_API_BASE_URL", apiBaseUrl);
+    const { client } = createTestClient();
+    server.use(http.get(`${apiBaseUrl}/network-error`, () => HttpResponse.error()));
+
+    // When
+    const request = client.request({
+      path: "/network-error",
+      responseSchema: valueSchema,
+      authentication: "none",
+    });
+
+    // Then
+    await expect(request).rejects.toBeInstanceOf(TypeError);
+  });
 });