feat(homekit): add ONVIF motion detection support

- implement ONVIF motion watcher to handle motion events
- add configuration options for motion hold time and ONVIF URL
- remap motion mode from "onvif" to "api" for compatibility
- log ONVIF motion watcher activity for better debugging

feat(onvif): implement event subscription for motion detection
- create PullPoint subscription to receive motion events
- implement methods for pulling messages and renewing subscriptions
- handle event requests and responses specific to motion detection

test(onvif): add unit tests for motion event parsing and subscription
- create tests for parsing various motion event XML responses
- verify correct handling of multiple notifications and edge cases
- test resolving event addresses for ONVIF clients

fix(hksv): improve motion detection logging
- log warnings when accessory or character not found during motion detection
- log number of listeners notified during motion state changes

feat(hap): add listener count method
- introduce method to retrieve the number of listeners for a character

feat(onvif): enhance ONVIF client with event URL handling
- extract event URL from ONVIF device response for subscription management

pkg/hksv/hksv.go

@@ -600,15 +600,19 @@ func (s *Server) GetImage(conn net.Conn, width, height int) []byte {
 // SetMotionDetected triggers or clears the motion detected characteristic.
 func (s *Server) SetMotionDetected(detected bool) {
 	if s.accessory == nil {
+		s.log.Warn().Str("stream", s.stream).Msg("[hksv] SetMotionDetected: accessory is nil")
 		return
 	}
 	char := s.accessory.GetCharacter("22") // MotionDetected
 	if char == nil {
+		s.log.Warn().Str("stream", s.stream).Msg("[hksv] SetMotionDetected: char 22 (MotionDetected) not found")
 		return
 	}
 	char.Value = detected
-	_ = char.NotifyListeners(nil)
-	s.log.Debug().Str("stream", s.stream).Bool("motion", detected).Msg("[hksv] motion")
+	listeners := char.ListenerCount()
+	err := char.NotifyListeners(nil)
+	s.log.Debug().Str("stream", s.stream).Bool("motion", detected).
+		Int("listeners", listeners).Err(err).Msg("[hksv] motion")
 }
 
 // MotionDetected returns the current motion detected state.