Issue Promotional Grants

Issue a promotional token grant to a client using existing or newly created promotional tokens.

This endpoint finds an existing promotional token and issues a single grant to the client. If no promotional tokens exist, it creates a new one with a safe priority (10) to avoid conflicts. This prevents the priority conflicts that occur when creating tokens with priority 1.

Args: client_id: ID of the client to issue grant to request: Promotional grant request with amount, expires_at, and priority funding_service: Service for issuing token grants token_service: Service for finding/creating promotional tokens user: Authenticated admin user

Returns: Dict containing details of the issued grant

Raises: ValidationError: If promotional token creation fails or client not found