fix(test): resolve Feishu hoisted mock export syntax error (#32128)

- Remove vi.hoisted() wrapper from exported mock in shared module
  (Vitest cannot export hoisted variables)
- Inline vi.hoisted + vi.mock in startup test so Vitest's per-file
  hoisting registers mocks before production imports

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

extensions/feishu/src/monitor.test-mocks.ts

@@ -1,6 +1,6 @@
 import { vi } from "vitest";
 
-export const probeFeishuMock: ReturnType<typeof vi.fn> = vi.hoisted(() => vi.fn());
+export const probeFeishuMock: ReturnType<typeof vi.fn> = vi.fn();
 
 vi.mock("./probe.js", () => ({
   probeFeishu: probeFeishuMock,