What did I fry? Jumper cables backward, now no start

Is it possible the charger's cable clamps weren't making a good connection? 12.2 volts indicates a good but discharged battery. It should be up to 12.6 volts. Two hours is plenty of time to charge a good battery on the slowest rate.

Use a test light to check the fuses. There's two small holes on top of the plastic handle to stick the probe in. Look for any fuse where the test light lights up on one terminal but not the other one.

Also look for fusible links near the battery. Those are short pieces of wire spliced into larger diameter wires to form the weak link in the chain. The insulation will not burn or melt but it could smell hot when a wire burns open. That takes a little time, unlike a fuse that blows instantly. To test a fuse link wire, pull on it. If it acts like a wire, it's okay. If it acts like a rubber band, it's burned open.