mock.module('./executor') leaks across all files in the same batch because
Bun runs test files in a directory in parallel. The afterAll restore trick
doesn't work when other files load the module concurrently at startup.
Moving the leak test to its own subdirectory (leak/) ensures CI's batch
runner isolates it in a separate bun test invocation, preventing executor
mock contamination in executor-resolution.test.ts and index.test.ts.
YeonGyu-Kim