IrisShaders/Iris — reverse-engineered prompt

Build me a modern open source Minecraft shaders mod that lets people use their existing OptiFine and ShadersMod shader packs on current Minecraft versions without having to modify the packs. I want it to focus on real playability, so good performance matters a lot, especially when paired with Sodium, and it should make a best effort to behave well in modded setups instead of fighting with modpacks.

Please make it generally usable with most popular shader packs, be clear about any known limitations or unsupported packs, and keep the project clean and maintainable so it is easy to improve later. If it makes sense for this codebase, support the usual modern mod loader setups people expect here.

I also want the basic docs someone would need to build it, run it, and understand what works today versus what is still incomplete compared with OptiFine. Keep the experience practical and polished rather than experimental. Look up current docs online if you need to.