reel-recut — spec-driven short-form talking-head edit

Turns a raw (or lightly-edited) vertical talking-head reel into a finished short-form look. The four signature elements:

1. Persistent title banner (top, rounded accent-color box, heavy weight, UPPERCASE, 1-2 lines)
2. Karaoke captions (bottom third, bold white + thick black stroke, short cleaned phrases, ~2s each)
3. Callout boxes for an aside or the comment-keyword CTA (mid-screen, same box style)
4. Tight "talking over myself" pacing — inter-phrase pauses silence-cut out so phrases butt together

The existing music/B-roll/audio are kept. The whole edit is described in ONE JSON "spec" and rendered by scripts/build_reel.py in a single pass.