- Remove premature all_dex.count() before filters are applied (was a
full-table COUNT(*) before any WHERE clauses)
- Add limit parameter (default 500) to cap unbounded result sets
- Materialize queryset into list once and use len() for count, avoiding
a second COUNT(*) query
- Remove unused all_sets variable (blocked pre-commit ruff check)
Closes#102
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>