feat: add native YouTube SABR playback

[Priveetee]

Summary

• add native stateful SABR playback for YouTube videos and livestreams
• keep live sessions progressing across evolving media windows, missing segments and transient stalls
• expose every advertised audio, video and codec choice to the player
• recover rejected YouTube player contexts without restarting the stack
• classify scheduled, restricted and members-only videos for the frontend
• include active livestreams in subscription feeds
• preserve YouTube Takeout ordering while keeping large imports responsive

Runtime verification

• deployed commit 2f0a03ce0f0d8e1fc2d1ebf9fd27b3cf7162f0f3 on the beta instance
• validated image ghcr.io/typetype-video/typetype-server-beta@sha256:792f8047e4b6a642097f9b44510d24cdf332434f195dc24fc378ed8097eed0e8
• validated live playback in Chromium, Firefox and WebKit on the watch page and embed
• observed a continuous live session for about 22 minutes with no terminal or discontinuity error and a bounded media cache
• validated Watch Later, subscription live ordering and the supplied YouTube Takeout archive
• live quality and codec switching remains tracked separately in [Bug]: Live playback freezes after changing quality or codec TypeType#163 and does not block 1.1.0

Tests

• ./gradlew test
• ./gradlew check
• ./gradlew shadowJar
• git diff --check
• CI, OpenAPI and Docker workflows