Adds support for filtering events by type or actor pattern within namespace
subscriptions. Key changes:
- Add SubscriptionFilter type with EventTypes and ActorPattern fields
- Add SubscribeWithFilter to EventBroadcaster interface
- Implement filtering in EventBus with full wildcard pattern support preserved
- Implement filtering in NATSEventBus (server-side namespace, client-side filters)
- Add MatchActorPattern function for actor ID pattern matching
- Add comprehensive unit tests for all filtering scenarios
Filter Processing:
- EventTypes: Event must match at least one type in the list (OR within types)
- ActorPattern: Event's ActorID must match the pattern (supports * and > wildcards)
- Multiple filters are combined with AND logic
This implementation works alongside the existing wildcard subscription support:
- Namespace wildcards (* and >) work with event filters
- Filters are applied after namespace pattern matching
- Metrics are properly recorded for filtered subscriptions
Closes#21
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
