- Cross-platform path resolution (auto-detect Windows/macOS/Linux)
- GC reduction in score_candidates (1 table vs 6 per invocation)
- Decay/forgetting mechanism to prevent infinite data growth
- Sandbox for load() to prevent code injection via data file
- Cross-platform ensure_dir for mkdir on all platforms
- New config options: data_path, decay_enabled, decay_rate
- Update README with v5 features and cross-platform documentation