demo: DirectFB

it would be massive overkill, and probly a bit impractical, in reality, but DirectFB compiled with only wasi (no other imports) would be an awesome test of framebuffer and input.

I also need to look into sidecar-loading wasm, so I could load just directfb, and load a directfb program using separate wasm. This would mean that the loaded wasm-code would only need to be a directfb application, not the entire stack.

The issue proposes compiling DirectFB with only WASI imports and exploring sidecar-loading separate WebAssembly programs, but it names no files, tests, or entry points. First clarify the intended scope and implementation location; done should include a reproducible DirectFB demo and a defined separate-module loading path.

Written by the indexing model from the issue text.