Implement SaveSnapshot and GetLatestSnapshot methods on InMemoryEventStore
to satisfy the SnapshotStore interface, and add comprehensive tests covering:
- SaveSnapshot persists snapshots correctly
- GetLatestSnapshot returns most recent snapshot by version
- Behavior when no snapshot exists (returns nil, nil)
- Snapshot versioning is respected across actors
- Version ordering (higher version wins, not insertion order)
- Data integrity for complex, nested, and special character states
- Edge cases: zero version, large version, empty/nil state
Closes#4
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
