I'm sure there were switch modules in the classrooms, but when the controller software crashed, they lost their connection to the individual fixtures.

I'm not too familiar with lighting controls, but I seem to remember reading the documentation on one particular system which can be wired in a way so that if the controller disappears, the devices in each room will at least auto discover themselves and work independently. But it required a particular wiring topology, or maybe some kind of bridge device, that separated each space.