Problem: Transpiled Lua code from vim9script is not amenable to static
analysis, requiring manual cleanup or ignoring parts of our codebase.
Solution: Revert to pre-rewrite version of (low-impact) legacy plugins
and remove the vim9jit shim.
Problem: No type information for `vim.uv`.
Solution: Vendor https://github.com/LuaCATS/luv (which is what
luals bundles). This will allow other tooling to work out-of-the-box and
make these files available to users and plugins without the need for
`lazydev.nvim` etc.
