refactor(runtime/run): `start_comfyui()` (#127)

Also:
- Fix `comfyui` type hint.
- Add module docs.
- `_hiddenswitch_setup_polyfills()` only warn if exception.
- `_exit_hook()` with `main_globals`, `start_locals`.
- `_hiddenswitch_share_context_vars()`

Co-Authored-By: abel1502 <32196516+abel1502@users.noreply.github.com>