Command line interface for accessing the Open Web Index shards and slices.

feat: enhance query commands with async support and fixes master

- Add --async flag to query aggregate, stats, and sites commands - Fix query aggregate to auto re-aggregate partial results for count/sum - Fix query aggregate to show all rows (no truncation) - Add file counter to query aggregate progress - Document query slice, stats, sites, warc, and aggregate in detail - Add async wrapper to OWIDuckDBSelectExecutor for thread-pool execution