internal: move sys to core

[Young-Flash]

cc @peter-jerry-ye

[peter-jerry-ye-code-review]

‼️ This code review is generated by a bot. Please verify the content before trusting it.

Here are three observations from the provided git diff output:

1. Version Bump in moon.mod.json:

   • The version in moon.mod.json has been updated from 0.4.16 to 0.4.17. This is a common practice when releasing new features or bug fixes. However, ensure that this version bump is intentional and aligns with the project's versioning strategy.

2. Deletion of ffi and Related Files:

   • Several files related to the Foreign Function Interface (FFI) have been deleted, including ffi.mbti, moon.pkg.json, sys_js.mbt, sys_native.mbt, and sys_wasm.mbt. This suggests a significant refactoring or removal of FFI functionality. Ensure that this deletion is intentional and that no dependent code relies on these files.

3. Deletion of sys Package Files:

   • The entire sys package, including moon.pkg.json, sys.mbt, sys.mbti, and sys_test.mbt, has been deleted. This indicates a major change in the project structure or functionality. Verify that this deletion is intended and that no other parts of the project depend on the sys package.

These changes suggest a significant refactoring or removal of functionality. Ensure that these changes are intentional and that they do not break any dependencies or expected behavior in the project.