- switched code to use the DI approach - the handle to `app` is handed over to the Plugin at initializaion. Keep in and supply down the execution chain, as needed
- new keyword added to support items starred with Obsidian core plugin 'Starred'
- the keyword is `starred:`
- detection and more user friendly handling of the general error condition when the File Explorer is not available
- new ribbon status icon shape to indicate the general error plus detailed error logged to the console