Operates on Vendors. In the Zuper client app this module is labeled "Vendor" for most companies, and "Supplier" for companies in the roofing industry — the API and data shape are identical either way. Vendors and Subcontractors share the exact same underlying schema and endpoints; they're distinguished only by the vendor_type field (VENDOR here) and the /vendors vs /subcontractors route prefix. Returns the column/field configuration used to render this module's list view — display labels, sort/lock/edit capability, and redirect targets per field, including custom fields (scoped separately per module: VENDOR vs SUBCONTRACTOR).