- Add HAAvailabilityConfig for per-entity availability_topic and payloads
- Defer discovery until MQTT connected; publish availability after discovery
- HASensor/HANumber: optional suggested_display_precision in discovery
- HASerializer/HADictionary: extend for new keys; update device types and mocks
- Docs and examples reflect availability and precision usage
- Tests updated for discovery and availability behavior
- Ignore .cursor/ in repo root