Added extensive test coverage including:
- Edge cases with optional field type validation
- Unicode and special character handling
- Very long messages and timestamps
- Custom field preservation (arrays, objects, nested data)
- Performance tests with large batches (1000, 5000, 10000 lines)
- Mixed valid/invalid line handling
- Empty string handling for optional fields
- Duration formatting edge cases
- Worker ID edge cases
All 67 tests passing, performance target met (<1s for 1000 lines, <5s for 10000 lines).
Co-Authored-By: Claude Worker <noreply@anthropic.com>