Document that EventStore interface has no Update/Delete methods, enforcing
append-only semantics by design. Events are immutable once persisted.
Changes:
- Update EventStore interface documentation in event.go to explicitly state
immutability guarantee and explain why Update/Delete methods are absent
- Add detailed retention policy documentation to JetStreamConfig showing
how MaxAge limits enforce automatic expiration without manual deletion
- Document JetStreamEventStore's immutability guarantee with storage-level
explanation of file-based storage and limits-based retention
- Add comprehensive immutability tests verifying:
- Events cannot be modified after persistence
- No Update or Delete methods exist on EventStore interface
- Versions are monotonically increasing
- Events cannot be deleted through the API
- Update README with detailed immutability section explaining:
- Interface-level append-only guarantee
- Storage-level immutability through JetStream configuration
- Audit trail reliability
- Pattern for handling corrections (append new event)
Closes#60
Co-Authored-By: Claude Code <noreply@anthropic.com>
