fix(homekit): fix HKSV recording by correcting HDS protocol and adding GOP buffering

The HKSV recording was failing because:
1. The dataSend.data message structure was wrong - `packets` was a flat integer
   instead of an array of objects with `data` and `metadata` fields matching
   the HAP-NodeJS specification
2. Each video/audio frame was sent as a separate mediaFragment, but Home Hub
   expects GOP-based fragments (~2-4 seconds of accumulated data)
3. Large fragments were not chunked (max 256 KiB per chunk)

Changes:
- Fix HDS dataSend.data message structure to use proper packets array with
  nested data/metadata (dataType, dataSequenceNumber, dataChunkSequenceNumber,
  isLastDataChunk, dataTotalSize)
- Add 256 KiB chunking for large media fragments
- Buffer moof+mdat pairs in hksvConsumer and flush on keyframe boundaries
  (GOP-based fragmentation)
- Pre-start consumer at pair-verify for instant init segment delivery
- Add write-response support to HAP PUT handler for ch131 DataStream setup
- Fix HAP service linking to match HAP-NodeJS reference
- Add default SelectedCameraRecordingConfiguration (ch209) value
- Start continuous motion generator at pair-verify with dedup protection

pkg/hap/camera/accessory.go

@@ -40,10 +40,8 @@ func NewHKSVAccessory(manuf, model, name, serial, firmware string) *hap.Accessor
 	}
 	acc.InitIID()
 
-	// CameraOperatingMode links to RTPStreamManagement and RecordingManagement
-	operatingMode.Linked = []int{int(rtpStream.IID), int(recordingMgmt.IID)}
-	// CameraEventRecordingManagement links to DataStreamManagement and MotionSensor
-	recordingMgmt.Linked = []int{int(dataStreamMgmt.IID), int(motionSensor.IID)}
+	// HAP-NodeJS: only RecordingManagement links to DataStreamManagement
+	recordingMgmt.Linked = []int{int(dataStreamMgmt.IID)}
 
 	return acc
 }
@@ -71,10 +69,8 @@ func NewHKSVDoorbellAccessory(manuf, model, name, serial, firmware string) *hap.
 	}
 	acc.InitIID()
 
-	// CameraOperatingMode links to RTPStreamManagement and RecordingManagement
-	operatingMode.Linked = []int{int(rtpStream.IID), int(recordingMgmt.IID)}
-	// CameraEventRecordingManagement links to DataStreamManagement, MotionSensor, and Doorbell
-	recordingMgmt.Linked = []int{int(dataStreamMgmt.IID), int(motionSensor.IID), int(doorbell.IID)}
+	// HAP-NodeJS: only RecordingManagement links to DataStreamManagement
+	recordingMgmt.Linked = []int{int(dataStreamMgmt.IID)}
 
 	return acc
 }