* Block plugins from reading or writing app config and cloud credentials
Add a denied-filename registry to the plugin audit sandbox, seeded with OrcaSlicer's config (.conf/.ini) and the cloud refresh-token file. The deny is checked above the loading-mode read exemption and the allowed roots, so a plugin cannot reach these files even though they sit inside data_dir(), which is itself an allowed root. Case-insensitive prefix matching also covers the .bak/.tmp companions that hold the same data, and os.rename/os.remove are hooked alongside open so the files cannot be deleted or clobbered either.
