List and create courses via the Google Classroom API

Steps

1. Call GET https://classroom.googleapis.com/v1/courses (courses.list) with optional query params teacherId, studentId, or courseStates[] to enumerate courses the caller can view; requires scope https://www.googleapis.com/auth/classroom.courses or the read-only classroom.courses.readonly.
2. Call POST https://classroom.googleapis.com/v1/courses (courses.create) with a Course JSON body; name is required (1-750 chars) and ownerId is required (numeric id, email, or the literal "me"); requires scope classroom.courses.
3. Explicitly set courseState to "ACTIVE" in the create request if you want the course usable immediately, since an unspecified courseState defaults to PROVISIONED, which is visible only to the primary teacher and domain administrators.
4. For a Workspace admin to call on behalf of a teacher, create a service account in Google Cloud Console, have the domain super admin authorize its client ID for domain-wide delegation in the Admin console (Security > Access and data control > API Controls > Domain wide delegation) with the needed OAuth scopes, then impersonate the teacher when calling courses.create.
5. Remember non-admin callers can only create a course with themselves as ownerId, while domain admins can create courses owned by any user in their domain.