ensure_track_features didn't check lineage_id

[TeunHuijben]

_ensure_track_features checked for the "not computed" -1 sentinel on the
tracklet column only. A graph whose track_id column is filled but whose
lineage_id column is still all -1 (e.g. a writer that populates one but not
the other) took the "already exists, just activate it" path, so -1 was served
as a real lineage id.

_has_uncomputed_track_ids now takes both track-id keys and returns True if
either existing column holds -1. Missing columns are still ignored, so they get
computed from scratch as before. A sentinel in either column recomputes both,
since TrackAnnotator derives tracklet and lineage ids together.

Adds test_recompute_lineage_ids_when_only_lineage_sentinel_present, which
fails on main with assert -1 not in [-1, -1, -1, -1, -1, -1] on both the
memory and sql backends.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.95%. Comparing base (1de5412) to head (fbe55ff).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #293   +/-   ##
=======================================
  Coverage   93.95%   93.95%           
=======================================
  Files          60       60           
  Lines        3589     3592    +3     
=======================================
+ Hits         3372     3375    +3     
  Misses        217      217           

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