v0.4.0

chore(release): bump to v0.4.0

### Added
- Memory-mapping support for large files (>64MB) with automatic fallback
- Ultra-fast mode (--ultra/-u) that skips comment analysis for maximum speed
- Skip empty files option (--skip-empty) to exclude zero-byte files from analysis
- Custom benchmark script with detailed performance metrics
- Enhanced benchmark scripts with configurable runs and comparison tools

### Improved
- Significant performance improvements through memory-mapped I/O for large files
- Optimized analyzer with better buffer reuse and reduced allocations
- More efficient traversal with parallel processing optimizations
- Fixed clippy warnings for better code quality (type complexity, unnecessary clones)

### Changed
- Default behavior now uses memory mapping for files larger than 64MB
- Improved error handling and fallback mechanisms for file reading