Add context menu for vault actions and trash functionality

- Add UiButtonContext component for context menu support on buttons
- Implement vault trash functionality using trash crate
- Move vaults to system trash on desktop (with fallback to permanent delete on mobile)
- Add context menu to vault list items for better mobile UX
- Keep hover delete button for desktop users

src-tauri/Cargo.toml

@@ -49,6 +49,7 @@ tauri-plugin-os = "2.3.2"
 tauri-plugin-persisted-scope = "2.3.4"
 tauri-plugin-store = "2.4.1"
 thiserror = "2.0.17"
+trash = "5.2.0"
 ts-rs = { version = "11.1.0", features = ["serde-compat"] }
 uhlc = "0.8.2"
 url = "2.5.7"