Movie preset, sports track balls.

[adityaraj-09]

Adds a Polarcut-style movie preset for cinematic clips, and makes sports a real follow-cam instead of a generic person chase.

• movie preset (locked camera): detect the clip first, then lock one crop per shot. Hard-cuts on scene/subject changes. No zoom breathing. Face-centered seats, not ByteTrack IDs. Presence gate so we don’t park on empty space. Two-shot only when both faces fit 9:16. Title cards and wide shots (tiny person / no person) lock to frame center so logos and establishing frames stay composed.
• Faster movie path: detect-only YOLO (yolo11n.pt), imgsz=512, analyze every other frame, skip pose/saliency/masks. Optional --fast for more skipping.
• sports follow-cam: track ball + nearest player, hold the same athlete ~1.2s, dead zone + quieter zoom, hard-cut on scene changes, ignore cars/bikes unless they’re the play, two-shot duels when they fit, lead the sprint. Sports still follows; movie still does not.

Test plan

• verthor clip.mp4 out.mp4 --preset movie — no per-frame hunt; hard cuts on scene changes
• Title card / logo shot stays centered
• Wide establishing shot (small subject) stays centered, not cropped to a side character
• Two people close together can share a frame; far apart stay single
• verthor match.mp4 out.mp4 --preset sports — follows the ball-carrier, not random crowd/cars
• Scene cuts in sports snap; motion inside a play eases
• --preset talking_head / existing presets still behave as before