Move CodeWorld-specific JavaScript integrations into codeworld-api library

As of #1362, `web/run.html` is supposed to be independent of which client-side framework is used by the application code. However, it still loads some CodeWorld-specific JavaScript for:

1. The debugging UI
2. The screen recording feature.

Ideally, the app-side code for these features would be moved to `codeworld-api`, and the environment-side implementation would be made as clean as possible. One could even imagine defining some kind of a generic shim so that (1) a different framework like reflex-dom can implement their own development features to interact with running apps, and integrating them with the development environment in the same way; and (2) a different programming environment could also integrate debugging tools that can introspect code using codeworld-api as a library.