Stream now supports SRT as a drop-in replacement for RTMP

Introduced support for SRT (Secure Reliable Transport) protocol as a new ingest option for Cloudflare Stream Live and Stream Connect. This includes the ability to translate between SRT and RTMP, allowing users to leverage SRT's benefits (lower latency, better resilience) while maintaining compatibility with existing RTMP infrastructure. The implementation supports adding/removing SRT/RTMP outputs without restarting streams and scales to tens of thousands of concurrent streams.