Replace Excel-based undelivered comparison with DB queries for all four
sites. The engine anchors on actual scan_time, reverse-lookups handover
batches, and compares expected vs actual waybill-by-waybill.
Shunxin SF waybills: use COUNT(*) instead of COUNT(DISTINCT piece_no)
since SF piece numbers are random and not derivable from the waybill.
Changes:
- db_compare.py: new module with compare_site_date(), compare_site_batch(),
write_result_excel(), and POST /compare API endpoint
- runtime.py: switch _site_undelivered_handler from compare.write_site_file
(Excel) to db_compare (DB); downloads succeed independently of comparison
- server.py: add POST /compare endpoint with date validation
- docs: implementation plan for Shunxin DB comparison
Co-Authored-By: Claude <noreply@anthropic.com>
