Search G2X contract vehicles

Searches bounded contract-vehicle definitions such as GWACs and BPAs. It returns linked vehicle records, not a list of vehicles held by a particular company. Continuation is capped at four pages; further research continues in the signed-in product. Invoke from an enabled G2X page surface. A signed-in account receives the same fields and results the G2X page shows that account; a signed-out viewer receives the public projection. Follow a returned continuation cursor instead of increasing the limit.