How to reproduce:
1. Create any Unity project
2. While the project is opened, navigate to the root folder and delete the "Library" folder
3. Observe the results

Expected results: The whole Library or some files can't be deleted since they are currently used by the Engine and there is a protection from deleting them
Actual results: The whole Library can be deleted and project crashes

Reproducible with: 6000.0.61f1, 6000.2.8f1, 6000.3.0b8, 6000.4.0a3

Reproducible on: macOS Tahoe 26 (M1)
Not reproducible on: Windows 11

Note: Some files in Windows can't be deleted since the protection from deletion works, and the project doesn't crash in this case