When no position filters are applied, `final_players` is a lazy Peewee queryset
with `ORDER BY RANDOM() LIMIT n`. Iterating it twice (once to build player_ids,
once for the response loop) executes two separate DB queries with different random
seeds, causing dex_by_player to be built for a different player set than returned,
silently producing empty paperdex for all players.
Add `final_players = list(final_players)` before building player_ids to ensure
both iterations operate on the same materialized result. Also fix pre-existing
syntax error in import statement and minor ruff lint issues in the same file.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Replace per-player/card Paperdex.select().where() calls with a single
batched query grouped by player_id. Eliminates N+1 queries in:
- players list endpoint (get_players, with inc_dex flag)
- players by team endpoint
- cards list endpoint (also materializes query to avoid double count())
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
