v0.1.0 (01 Feb 2026)

Add cryptographic log signing with hash chaining and integrity tests

- Introduce LogSigner component for cryptographic log integrity
- Implement hash chaining to detect log tampering, removal, or injection
- Support optional HMAC signing via secret key for authenticity
- Keep logger lightweight, dependency-free, and append-only
- Ensure signatures are computed on the exact written log content
- Add comprehensive tests to validate hash chain integrity
- Add tests to detect log modification, deletion, and injection
- Add tests for both unsigned and HMAC-signed log chains

v0.1.0