[SDK: Node] Add Vehicles endpoints/interface

[infinityplusone]

Changes

• Add Vehicles endpoints to the Node SDK:
  • listVehicles
  • getVehicle
  • listVehicleAwardees
• Add IDV endpoints to the Node SDK:
  • listIdvs
  • getIdv
  • listIdvAwards
  • listIdvChildIdvs
  • listIdvTransactions
  • getIdvSummary
  • listIdvSummaryAwards
• Extend shaping support (ShapeConfig + explicit schemas) to validate/materialize Vehicle + IDV shapes.
• Update docs + changelog.

Why

• Bring Node SDK endpoint coverage up to parity for Vehicles. Closes makegov/tango#1327.
• While here, wire the IDV endpoints since Vehicles are tightly coupled to IDVs in real usage.

Testing

• npm test
• If vitest worker pool crashes in your environment: npx vitest run --pool=forks

Closes makegov/tango#1327