[davior]

Hold before merging: an adversarial parity review of the spec path is still running: two agents are trying to find any note that the spec path renders differently. Once it reports, I'll fold in anything it confirms and then mark this ready.

Summary

This is the second Phase 0 step in docs/gecko-video-creator.md, after #206.

• segment() now goes through the VideoSpec. It imports the note as a spec (importer.py) and compiles it back to shots (compiler.py). Every render and every estimate is now built from a spec. The old walk and _bumper_shot are deleted from the app. segmenter.py keeps the Shot model and the block-reading helpers both sides use.
• POST /api/video/spec returns the spec for a note. It takes the same body as /estimate, so a selection and the dialog's options shape it exactly as they would a render. Nothing is rendered or stored.
• The original walk is kept verbatim as the reference copy in backend/tests/segment_reference.py. Every segmenter case, the 3,000 generated notes and real render() runs (ffmpeg faked) still have to match it exactly. When the planned chapter-mark fixes land, they change both together, or the reference copy is retired.
• The doc's Phase 0 status is updated.

No behaviour changes: the same shots, warnings and ffmpeg commands as before, held by the tests above.

Test plan

• pytest -q from backend/, as CI runs it: 1,285 passed, 1 skipped (that skip was already there).
• The 68 segmenter tests now run directly against the spec path and pass unchanged.
• Endpoint tests:
  • it returns a valid spec with provenance
  • a selection and the options shape it
  • another user's note gets a 404
  • invalid options get a 400
• Adversarial parity review reports clean, or its findings are fixed.
• CI green.

🤖 Generated with Claude Code

https://claude.ai/code/session_01PwaujUokXQAxnebBArpZuj

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