Dependency wavesoft/local-echo likely dead

[tryone144]

It appears development of wavesoft/local-echo has seized and the project is no longer actively maintained.

This has become troublesome as with the latest xterm.js v5, the input handling leads to flickering artefacts. This is most likely related to the way in which the screen is cleared and the current input printed afterwards. Since this project aims to provide a Shell-like environment to execute WASM-Binaries we might be better off in merging the required functionality into this repo and updating/fixing its behaviour.

"Similar" projects like <webassembly.sh> and <wasmerio.sh> probably use a similar approach. However, I haven't been able to attain up-to-date sources for these projects.

An alternative would be to research if there are existing minimal shells that we could execute in our context. However, this might not be feasible with the current architecture of the task runners.