Re-verify the license

Force verification against the license service and return the new state. A checkout completion alone cannot activate a license. An unreachable service leaves the cached entitlement intact. Requires the **viewer** role; remains available while management is locked.

curl -X POST "https://example.com/api/license/refresh"

{  "state": "active",  "tier": "string",  "daysLeft": 0,  "lockedReason": "string",  "serial": "string",  "lastVerifiedAt": 0,  "expiresAt": 0,  "validUntil": 0,  "development": true}