Fix DEL character insertion in Minecraft 1.1 with deAWT on macOS

[slbls]

This PR fixes #29 by addressing the DEL character (ASCII 127) insertion issue that occurs when running Minecraft 1.1 with deAWT enabled on macOS.

When deAWT removes AWT Frame and Canvas usage to fix graphical issues on Apple silicon, it also removes AWT's platform-specific key mapping functionality. Combined with a character validation logic change from Minecraft 1.0 to 1.1 (which accepts any character with ASCII value > 32 to support international languages), this causes the DEL character to be inserted as a visible character in text fields after performing deletion operations.

The fix modifies the bytecode validation to reject ASCII values ≤ 127 instead of ≤ 32, excluding DEL while preserving extended ASCII support for international characters.

Java isn't a language I typically work with, so please feel free to leave stylistic and idiomatic feedback as well.

[slbls]

@Lassebq, here's a second attempt with stricter constraints. Interested to know if there's an established way to get the currently running version of the game to further clamp down when this patch is applied.

[Lassebq]

I will need to introduce some runtime remapping to easier analyze these patches in vanilla and make modified classes easier to read. I did have a few nits on this PR but I accepted it anyway, it does what it needs to do without possible conflicts or false positives

[slbls]

Thanks for helping me see this through and bearing with me while I got my bearings. Let me know if there's any follow-ups that I can help with. I'm happy to address any nits or play a part in helping with making modified classes easier to read.