This PR introduces a comprehensive stream publish token system that
prevents race conditions when multiple publishers attempt to publish to
the same stream URL simultaneously across different protocols (RTMP,
WebRTC, SRT).
* Race Condition Issue: Multiple publishers could create duplicate
sources for the same stream when context switches occurred during source
initialization in SRS's coroutine-based architecture
* Cross-Protocol Conflicts: Different protocols (RTMP, RTC, SRT) could
simultaneously publish to the same stream URL without coordination
* Resource Management: No centralized mechanism to ensure exclusive
stream publishing access
---------
Co-authored-by: OSSRS-AI <winlinam@gmail.com>
