* Restyle UserInputLabel and refactor its usages to have all input its data sent from Rust
* Replace the welcome screen quick buttons with ones sent by backend
* Add the ShortcutLabel widget to the backend
* Replace hints bar with a backend-controlled layout; show mouse icons in place of mouse labels
* Replace the title attribute with custom FloatingMenu tooltips
* Separate tooltip labels and descriptions into two styled blocks
* Move keyboard shortcut tooltips to a separate section at the bottom
* Update shortcut key styling in tooltips and hints bar
* Fix .to_string()