90-second demo grant
No auth — this is the keyless trial. Mints a 90-second grant, but
only for verb: "demo_write" on a target starting with demo-.
Anything else is a 400. Use it to prove the intercept loop
(check → grant → check → ALLOW) without signing up; switch to
POST /v1/keys for real verbs. Sandbox grants are not tenant-scoped.
Request
This endpoint expects any.
Response
Sandbox grant created. Use it with POST /v1/check within 90 seconds.
Errors
400
Bad Request Error