refactor: Improve backup retention logic to be non-recursive and folder-specific, enabling directory pruning and updating PyInstaller build settings.

ProBackup.spec

@@ -100,9 +100,11 @@ exe = EXE(
     debug=False,
     bootloader_ignore_signals=False,
     strip=False,
-    upx=False,
+    upx=True,
     upx_exclude=[],
     runtime_tmpdir=None,
     console=False,
+    disable_windowed_traceback=False,
+    argv_emulation=False,
     icon='icon.ico',
 )