Port the SYB ERP HTTP client from the upstream cmautobuy project. The
package is stdlib-only (no DB, no gin), so client.go, columns.go, ocr.go
and their httptest suites carry over almost verbatim; only the package
name and doc references changed.
Add on top of the port:
- models.SYBSession + gorm SessionStore, so a restart does not force a
fresh captcha. Cookies are credential-equivalent and carry json:"-".
Expired sessions read as absent because SYB has no rolling renewal.
- config.Extend.SYB. Non-secret settings live in settings.yml;
username and password come only from GOAUTO_SYB_* environment
variables, so no credential lands in a tracked file.
- docs/12-syb-erp-interface.md, the ported interface contract.
The guard tests were mutation-checked: reverting json:"-" and renaming a
settings.yml key each make their test fail.
No import endpoint yet — that needs real credentials and live network
verification, which is Stage 2 of #48.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
