[sungmen999]

Summary

This PR has 31 commits from a deep audit of the pipeline and two feature branches. Grouped by area:

engine         lib/checkpoint.py enforces the decision-log, review, gate and budget contracts
tools          tool schemas, estimates and checks match their code
               audio_mixer tracks take offset_seconds and loop
               composition_validator also checks images[] and backgroundVideo
hyperframes    GSAP and three.js come from pinned npm installs, so renders work offline
               music fades are written as volume tweens
               an asset is restaged whenever its content changes (the size check missed this)
threejs_world  index.html has an import map for `three`, so the 3D world now renders
character      the scene is sized to the profile's canvas; figures are centred and on the ground
remotion       Explainer music ducks under narration
               titles split by grapheme
               the last cut holds to the end
               CalloutBox renders lines and bullets
comfyui / tts  bundled MiniMax H3 (local) and Qwen-Image-2.1 workflows
               comfyui_tts speaks through VoxCPM2
backlot        playback and scroll survive re-renders; project state carries an ETag
skills / docs  pipeline skills and manifests match the schemas and code; AGENT_GUIDE.md is split by section
ci / qa        CI runs Python 3.10 and 3.11 with Playwright and type-checks remotion
               the QA scripts exit 1 when a step fails

remotion-composer/package.json gains two dependencies, both installed by make setup:

• gsap 3.14.2, under GSAP's Standard "no charge" license
• three 0.181.2, under MIT

tools/gsap_runtime.py and tools/three_runtime.py copy these into each workspace. When they are not installed, both fall back to the pinned CDN URLs.

Evidence

Full suite after: 4154 passed, 26 skipped, 0 failed, and make lint passes. The suite ran against an ffmpeg build that has libass, drawtext and libvorbis.

Each fix below was checked with a real render:

• threejs_world
  • Before: the page logged Failed to resolve module specifier "three". The canvas stayed black on "BUILDING WORLD GRAPH…", yet the render exited 0.
  • After: terrain, landmarks and the camera path render. Two runs produced the same frames: one with all outbound traffic except localhost denied, one online through the CDN fallback.
• GSAP offline
  • Before: with network denied, the page logged Failed to download CDN script … gsap.min.js and Cannot read properties of null (reading 'timeline'), and the render exited 1.
  • After: the render completes and the tweens run.
• Character scene
  • Before: the 1280x720 scene sat in the top-left of the 1920x1080 canvas, and the figures' feet were cut off. A vertical re-render then reused the stale landscape copy, which had the same byte size, so the lower half was black.
  • After: video_compose renders at the default 1920x1080 and at youtube_shorts 1080x1920 both fill the frame.
• Explainer ducking: the music band drops 9.1 dB under speech. With ducking off it stays flat.
• HyperFrames music fade: the music measures −49.3 dB at the start, −31.5 dB in the middle and −49.1 dB at the end.

Merge Danger

Door: two-way

This PR changes only code, tests, skills and docs, with no data migration. Reverting it restores the old behaviour.

Blast Radius: wide

• It touches the checkpoint engine. Stricter gates can block runs that used to pass without notice.
• It changes the Remotion, HyperFrames and Three.js render paths.
• It changes the skill text agents follow.
• make setup installs two more npm packages.

🤖 Generated with Claude Code