Add timestamp offset tracking for late subscribers joining live streams.
Keyframe detection mode now properly switches to SEND_ALL once a keyframe
is available. Added waitingForKeyframe flag to track state when waiting for
the first keyframe before allowing frame sending.

Changes:
- Add publisherTimestampOffset field for tracking publisher timestamp
- Add waitingForKeyframe flag to control frame sending before first keyframe
- Initialize streamStartTS to 0 for late subscribers to generate
  proper relative timestamps
- Enhance debug logging for keyframe availability and codec state
- Clean up unused code in RTMP protocol encoders/decoders

The decode(byte[]) method was incorrectly processing LEB128 encoded data,
treating it as big-endian when LEB128 is by definition little-endian
(Little Endian Base 128).

Key fixes:
- decode(byte[]): Now correctly reads bytes in little-endian order, where
  the LSB 7-bit group comes first. Each byte is processed sequentially
  with the 7 data bits shifted into position.
- encode(byte[]): Simplified to delegate to decode, as the original logic
  was fundamentally broken for LEB128 encoding.

LEB128 format per AV1 spec:
- Each byte contains 7 bits of data (LSB) + 1 continuation bit (MSB)
- Bytes are read in the order they appear in the packet
- First byte contains least significant 7-bit group

Example: value 150
- Old (wrong): Would read bytes in big-endian order, producing incorrect results
- New (correct): Reads [0x96, 0x01] as: (0x16 << 0) | (0x01 << 7) = 22 + 128 = 150

Also fixed test data with correct LEB128 expected values.

…olEncoder.java

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

…olEncoder.java

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

…olEncoder.java

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

…olEncoder.java

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

PlayEngine changes:
- Track audio and video base timestamps separately for late subscribers
- Both audio and video now start at ts=2 for proper A/V sync
- Reorder playLive() to send audio config before keyframe (DTS ordering fix)
- Add debug logging for video frame delivery path

RTMPConnection changes:
- Reduce BytesRead acknowledgement interval from 1MB to 128KB
- More frequent acknowledgements improve encoder compatibility
- Add debug logging for BytesRead messages

RTMP codec improvements:
- Enhanced extended timestamp handling for timestamps >= 0xFFFFFF
- Per-channel timestamp offset tracking for discontinuity compensation
- Improved timestamp delta calculations in encoder

Debug logging additions:
- ClientBroadcastStream: video reception and livePipe push logging
- VideoFrameDropper: state transition and frame drop decision logging
- TestRTMPUtils: comprehensive tests for RTMP utility methods

Proposed 2.0.26 release with RTMP encode/decode fixes