test(lobster): preserve execFile in child_process mock

extensions/lobster/src/lobster-tool.test.ts

@@ -17,9 +17,13 @@ const spawnState = vi.hoisted(() => ({
   spawn: vi.fn(),
 }));
 
-vi.mock("node:child_process", () => ({
-  spawn: (...args: unknown[]) => spawnState.spawn(...args),
-}));
+vi.mock("node:child_process", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("node:child_process")>();
+  return {
+    ...actual,
+    spawn: (...args: unknown[]) => spawnState.spawn(...args),
+  };
+});
 
 let createLobsterTool: typeof import("./lobster-tool.js").createLobsterTool;