Expose session.tracks for DISTANCE kinematics on VideoTrackingSession.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: AlexBodner

sports/common/video_tracking.py

@@ -18,6 +18,11 @@
     gap_fill_speed_transforms,
     replay_gated_transforms,
 )
+from sports.common.kinematics import (
+    PlayerTrack,
+    collect_tracks,
+    compute_kinematics,
+)
 from sports.common.goalkeeper import apply_goalkeeper_teams, derive_gk_locks
 from sports.common.team import (
     TeamLocks,
@@ -64,6 +69,7 @@ class VideoTrackingSession:
     _speed_transforms: dict | None = field(default=None, repr=False)
     _gap_filled_transforms: dict | None = field(default=None, repr=False)
     _minimap_transforms: dict | None = field(default=None, repr=False)
+    _tracks: dict[int, PlayerTrack] | None = field(default=None, repr=False)
 
     def team_locks(self) -> TeamLocks:
         """Return clip-level team locks, cached."""
@@ -112,6 +118,19 @@ def minimap_transforms_by_frame(self) -> dict:
             self._minimap_transforms = build_minimap_transform_map(self.kp_by_frame)
         return self._minimap_transforms
 
+    @property
+    def tracks(self) -> dict[int, PlayerTrack]:
+        """Per-track cumulative distance from gated homography (not gap-filled)."""
+        if self._tracks is None:
+            raw = collect_tracks(self.iter_tracked())
+            self._tracks = compute_kinematics(
+                raw,
+                self.fps,
+                mode="homography",
+                frame_transforms=self._gated_speed_transforms(),
+            )
+        return self._tracks
+
     def iter_tracked(self):
         """Yield frame_idx and tracked detections with blocked ids removed."""
         for frame_idx, dets in self.frames: