How do I know if I bent a valve?

Hello,

On an interference engine if the timing belt breaks during engine operation, it is more than likely that the valves got bent at the least. It could also damage the engine.
Since you have a hard spot when you turn the engine, you could have bent valve(s).
Only way to know for sure is to take apart the cylinder head and take a look inside.

https://www.2carpros.com/articles/how-a-cylinder-head-works

I have attached the cylinder head removal and timing belt replacement instructions for your reference.

Please let me know of any questions.
Thank you.