Comprehensive audit system for security and compliance:
- middleware/audit.go: HTTP request/response auditing middleware
* Captures request details, user identity, response status
* Chains audit events with cryptographic hashes for tamper detection
* Configurable filtering for sensitive data redaction
- audit/chain.go: Blockchain-style audit log chaining
* Each entry includes hash of previous entry
* Tamper detection through hash verification
* Supports incremental verification without full scan
- checkpoint.go: Periodic integrity checkpoints
* Creates signed checkpoints for fast verification
* Configurable checkpoint intervals
* Recovery from last known good checkpoint
- rotation.go: Automatic log rotation and archival
* Size-based and time-based rotation policies
* Compressed archival with integrity seals
* Retention policy enforcement
- sealed.go: Cryptographic sealing of audit logs
* Digital signatures for log integrity
* HSM support preparation
* Exportable sealed bundles for external auditors
- verifier.go: Log verification and forensic analysis
* Complete chain verification from genesis to latest
* Detects gaps, tampering, unauthorized modifications
* Forensic export for incident response
