paper2video - paper/assets -> ppt-master deck -> pptx2video render -> narrated MP4

paper2video is a thin orchestrator with exactly one supported path. It does not author slides itself, does not synthesize audio itself, does not composite video itself, and does not gate QA itself. It resolves inputs and one shared trigger decision, then fully delegates:

paper.pdf
  -> skills/paper2assets/scripts/build_package.py       (shared package)
  -> assets/meta/paper_spec.md + assets/meta/narration.json
  -> ppt_options_contract.py resolve-ppt-trigger          (ONE trigger decision)
  -> installed ppt-master skill                          (full workflow, receives the trigger)
  -> installed pptx2video skill / CLI `bootstrap` then `render` (full workflow, receives the trigger)
  -> ppt_stage_validator.py audit-final-pptx-trigger      (proves the handoff held)
  -> video.mp4, video_no_subtitles.mp4, video.pptx