- Introduced tests for the plugin catalogue installation and update flows in `test_plugin_catalogue_install.py`.
- Added unit tests for the GitHub Releases plugin client in `test_plugin_github_releases.py`.
- Implemented IPC tests for the plugin manager Unix socket protocol in `test_plugin_ipc.py`.
- Created lifecycle and installation tests for the plugin manager in `test_plugin_manager_lifecycle.py`.
- Added tests for plugin manifest parsing in `test_plugin_manifest.py`.
- Developed tests for plugin filesystem layout and state management in `test_plugin_storage.py`.