revert: remove YouTube audio functionality (doesn't work)
YouTube blocks audio-only/hidden embed playback with a "Sign in to confirm
you're not a bot" gate → not reliably usable. All YT-audio reverted:
- embed-player.js + embed.css → state before the feature (audio-only card,
YT-album, buildYtAlbum, prewarm, mode-routing removed). Video embeds +
the YT/SC volume button remain.
- audio-player.js → YT backend (ytMode/ensureYT/playYouTube/playYouTubeList/…)
removed; only the blob-<audio> player + existing features.
- AudioEmbedService.js → audio:/video: mode parsing + data-embed-mode removed.
- audio.js → /yt-title oEmbed proxy removed.
- post-edit.ejs → audio/video choice on the embed button removed ([[embed:url]]
normal).
busters audio-player.js?v=28, embed-player.js?v=16, embed.css?v=8.
Co-Authored-By: Claude <noreply@…>