Verify (POST)

Verify VC status via Vault or Issuance depending on payload.

POST /verify

• Owner payload: { owner: string; vcId: string; vaultContractId?: string } → { vc_id: string; status: string; since?: string }

• Without owner: { vcId: string } → { vc_id: string; status: string; since?: string }

• Validation errors: vcId_required

• Errors: 500 verify_error

• Source: api/testnet/src/controllers/verifyController.ts:14-36