NuvioTV Custom 0.8.10-beta-nt6

This is the production-signed follow-up to the v0.8.10-beta-nt5 TV benchmark. It includes the
same verified Seekr frame-calibration release and is built by the protected GitHub Actions release
workflow using the fork's encrypted signing and backend configuration secrets.

Seekr frame calibration

• Automatically aligns Seekr preview timing to the actual rendered ExoPlayer release when local
  evidence is strong enough.
• Uses three safe timeline anchors and searches -3s, 0, and +3s around each cue to cover
  documented keyframe drift.
• Uses low-resolution luminance comparison plus robust median/outlier filtering.
• Rejects weak or ambiguous matches and falls back to the original timing without affecting
  playback.
• Keeps manual Preview Sync controls for fine adjustment and resets calibration for each release.
• Uses the existing player surface only: no stream proxy, second decoder, frame upload, or server
  processing.

See the custom feature guide for the comparison with normal Seekr
integration and its limitations.