The `preload_dependencies` function has been refactored to directly run
parsed programs instead of collecting all forms into a single `Program`
node. This simplifies the compilation pipeline by allowing each
dependency to be processed individually.
Additionally, the `VM::run_with_observer` method has been updated to
manage its stack and frames more cleanly, avoiding the need for
`eval_in_frame`. The main loop now correctly extracts expressions from
the `Program` node for source code emission.
Brummel
8fd2f2d113