Evaluate L5-MMP

Evaluate the five-game median-minutes persistence baseline over regular-season curated player box scores:

uv run nba-evaluate-l5-median-minutes-persistence \
  --seasons 2024-25 2025-26

The first five team-games for every team-season are excluded because L5-MMP requires five completed historical allocations. Each run writes per-player predictions, team-game metrics, aggregate season metrics, and metadata to an immutable directory below artifacts/rotation/l5_median_minutes_persistence/.