Add multi-database support allowing selection between SQL Server and
PostgreSQL via database.active config. Changes include dialect-aware
SQL generation, cross-database timestamp functions, PostgreSQL connection
URL builder, and psycopg dependency.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Add box schemas (BoxInfoResponse, BoxSaveRequest, BoxSaveResponse)
- Add box service with ERP view query and save logic (supports many2one append)
- Add box router with GET /box/info and POST /box endpoints
- Register exception handlers for InvalidZongpaiError, ZongpaiNotFoundError, DuplicateBoxItemError
- Update RequestValidationError handler to cover INVALID_BOX_NO and INVALID_QUANTITY
- Add 7 integration tests for box API
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
