Remove buggy hackSetProgram

[jtran]

hackSetProgram was a temporary hack, but it leads to multiple concurrent executions which causes hard-to-track-down bugs.

Related:

• Implement file life cycle API with rust #9280

[jtran]

This is causing race conditions where downstream data structures are getting out of sync with the KCL source that it originated from. We think that part of the solution is to tie data structures to their original source using a version number, the the original intent of the file Version. The problems seem rare enough right now that we think we can delay this until after first release.

A big question is, who owns what? With some of the lifecycle changes and my unfinished branch, we can make TS own the KCL source. But the derivative data structures like the scene graph need to be tied to that.

[jtran]

We'll probably need switch file to be implemented also. https://github.com/KittyCAD/modeling-app/compare/jtran/switch-file