SiputBiru/sb_nes ? reverse-engineered prompt

Build me a simple NES emulator in C that can open and play iNES ROM files, with a small SDL3 window for video output and basic keyboard input. It should be able to run the kind of demo ROMs shown in the README, like Super Mario Bros and Pac Man, and it’s fine if there’s no sound yet since audio support is not part of this version.

I only need support for iNES format ROMs with mapper 0 and mapper 2 for now, so don’t worry about the more advanced mappers or NES 2.0. Make it easy to build with the included build helper, and let me launch it from the command line by passing in a ROM path.

If you need anything from the latest SDL3 docs, look it up online. Also, make sure it’s organized cleanly enough that I can later extend it with audio and more mappers.