We fixed a few issues with scheduling classes and keeping them in sync with Google Calendar.
- When you add a new session to an existing class, it now takes over that class's settings automatically - capacity, credits, room, cancellation and penalty rules, and booking cut-off times. Anything you set yourself on the session is still kept as-is.
- The room inherited from the class is now included in the availability check, so double-bookings are caught before the session is saved.
- Classes without an instructor assigned are no longer skipped by Google Calendar sync, and their calendar entries no longer show an empty instructor line.
- If a class entry was removed from Google Calendar, updating the class now restores it instead of silently leaving it missing.
