Implement Apple's LL-HLS compliance requirements for EXT-X-PRELOAD-HINT and EXT-X-RENDITION-REPORT across all sibling renditions

Steps

1. Enable partial segments with EXT-X-PART entries and an EXT-X-PART-INF target duration in each media playlist
2. Add an EXT-X-PRELOAD-HINT tag pointing to the next not-yet-available part (or an upcoming key/map) so clients can request it early and have the origin or CDN edge hold the response open (block) until it's ready
3. Ensure every rendition's playlist advertises an EXT-X-RENDITION-REPORT for every sibling video, audio, and subtitle rendition in the same variant group, each carrying that sibling's last-known media sequence number and part number - Apple's authoring spec requires this on every rendition, not just the primary one
4. Support blocking playlist reload by honoring the _HLS_msn and _HLS_part query parameters on playlist requests so clients can long-poll for the next update instead of polling on an interval
5. Confirm your origin and CDN actually support long-poll/blocking requests for preload hints - an edge that doesn't will silently degrade you back to regular-latency HLS
6. Validate the output against Apple's HLS authoring/compliance tooling before shipping a player integration against it