API boxscore: empty per-athlete stats array in ESPN summary crashes boxscore (IndexError) #92

Symptom

get_game_boxscore(..., source="api") returns an empty DataFrame for some games, logging:

ERROR: 401604889 - Boxscore (API): list index out of range
ERROR: 401592369 - Boxscore (API): list index out of range

Root cause (upstream)

ESPN's summary endpoint (site.api.espn.com/.../summary?event={id}) sometimes lists an athlete in boxscore.players[].statistics[0].athletes with didNotPlay: false but an empty stats array, while the team's names labels list has 13 entries:

• 401604889 (Point Park at Robert Morris): M. Murphy, a starter, stats: [] — played 2 min with a fully zero stat line
• 401592369 (Southern Indiana at Michigan State): Javius Moore, bench, stats: [] — played 5 min with 1 FGA (a 3PA) and 1 TO

_boxscore_adapter (espn_api.py) passes the empty list through, and _build_player_rows (cbbpy_utils.py) indexes players[j]["stats"][i] per label → IndexError → the entire game's boxscore comes back empty.

The data exists elsewhere

This is purely a summary-endpoint gap, not missing data:

• HTML embed (source="html") carries full rows for both players (Murphy: 2 min all zeros; Moore's line present) and scrapes these games fine.
• ESPN core API has the complete line: sports.core.api.espn.com/v2/.../events/401592369/competitions/401592369/competitors/88/roster/5177372/statistics/0 returns minutes 5, FGA 1, 3PA 1, TO 1 for Moore.
• The summary's own plays array contains Moore's individual events (missed 3PT jumper at 5:03 Q1, turnover at 3:47 Q1), so PBP-side data is unaffected.

Fix direction

Keep the row rather than dropping the athlete like a DNP (dropping would lose a real starter and break API/HTML row-count parity). Options:

1. Pad short/empty stats in _boxscore_adapter (blanks/zeros) — cheap, but Moore's real stats would read as zero where HTML has them.
2. Backfill the missing line from the core API roster/statistics endpoint (one extra request only when an empty stats array is encountered).

Either way the IndexError should not take down the whole game's boxscore.