mix compile.arc (cratis_arc v0.1.0)

Regenerates TypeScript proxies after each compile. Opt in by adding the compiler:

def project do
  [
    # ...
    compilers: Mix.compilers() ++ [:arc],
    arc: [application: MyApp.Arc, output: "assets/src/arc"]
  ]
end

Without arc: [application: ..., output: ...] the compiler does nothing, so adding it to a project that does not use React is harmless. Under mix phx.server, Phoenix's code reloader runs the project's compilers, so proxies follow your edits.