Fix Windows file-locking error

[DrVinay]

On Windows, open file handles cannot be deleted, unlike Linux. System opened a temporary CSV log file but had no close() method, causing os.unlink() to fail in tests.

Changes made:
Added System.close() to system.py to release the CSV log handle
Updated test_create_system_registry.py to initialize system = None before try, then call system.close() in finally before unlinking the temp file.

This fixes the cross-platform inconsistency where tests passed in Linux CI but failed locally on Windows.

[jarcherNV]

Sorry we haven't got to reviewing this yet, and thanks for implementing this.

I think this is the right direction. Since System now owns an explicit file handle, can we also call system.close() from SystemManager.close_session() before deleting the session?

Right now this fixes the test cleanup path, but normal controller sessions still keep the CSV log file handle open after close_session(). That seems like the same Windows file-locking issue in the production lifecycle.

Could we add or update a SystemManager lifecycle test so closing a session also closes the underlying System log handle? That would cover the real path, not just the direct create_system() test.