Fix ESM parse error for isbinaryfile mock in tests

[antonym]

Summary

• jest.mock('isbinaryfile') without a factory still attempts to parse the real ESM-only module to auto-generate the mock, causing a SyntaxError: Cannot use import statement outside a module failure
• Provide an explicit factory function () => ({ isBinaryFile: jest.fn() }) so Jest never loads the real module

Follows up on #132 which addressed this for CI but the fix didn't fully prevent the ESM parse on all environments.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

The change correctly updates the isbinaryfile mock to explicitly export the isBinaryFile function, which is necessary for proper ESM module mocking. The mock is used correctly in the test on line 177 where it's destructured, and the mock behavior (using mockResolvedValueOnce) is appropriate for the async function.

Files Reviewed (1 file)

• tests/unit/app.test.js - ESM mock update for isbinaryfile module