feat: add PASS_NETWORK ball possession and collaboration overlays (PR 7)

[AlexBodner]

Summary

• Ball attach + cache, possession/pass scan, and collaboration aggregation on VideoTrackingSession
• New Mode.PASS_NETWORK (opt-in; not in ALL) with carrier/pass/turnover overlays, radar minimap, and a short top-collaborators end-card
• Lane quality / pass_options deferred to PR8 (PassQualityScorer is a no-op here; detection does not gate on scores)

Ball tracking here uses the dedicated ball YOLO only (football-ball-detection.pt). We are not adding a fallback that fills gaps with player-detector ball boxes when the dedicated model drops mid-flight — that helped recall on some hard clips in earlier experiments, but it adds a second ball path and caching story we do not want in this PR. If dedicated-ball gaps become a real issue in production demos, it can be a focused follow-up.

Demo

PASS_NETWORK — ball attach, pass/turnover overlays, collaboration arcs, and end-card (clip: 10 passes, 1 turnover on the sample video):

All demos

Run

cd examples/soccer
python main.py \
  --source_video_path data/08fd33_0.mp4 \
  --target_video_path data/renders/pr7-pass-network.mp4 \
  --device mps --mode PASS_NETWORK \
  --ball-model-path data/football-ball-detection.pt

Requires ball weights from ./setup.sh. Prefer a full clip for meaningful pass recall. Analytics default tracker is botsort (--tracker bytetrack / botsort_nocmc available).

Test plan

• --mode PASS_NETWORK renders without crash; ball attaches when detected
• Passes/turnovers overlay; end-card shows top collaborators when passes exist
• Quality fields on inferred passes may be null (scoring is PR8)
• DIRECTION / SPEED / DISTANCE / ALL unchanged
• Legacy BALL_DETECTION unchanged

[AlexBodner]

Cleanup: moved image_displacement_to_pitch_m into homography (SPEED no longer imports pass_pitch), prefer forward RANSAC, python_requires>=3.9.