Refactor mouse and keyboard handlers with shared actions

- Extract common action functions to eliminate code duplication
- Mouse left-click toggles folder open/close
- Mouse right-click plays selection (identical to Enter key)
- Add confirmation popup for library refresh operation
- Improve popup visibility with Clear widget

src/state/mod.rs

@@ -36,6 +36,7 @@ pub struct AppState {
     pub visual_mode: bool,
     pub visual_anchor: usize,
     pub saved_expanded_dirs: HashSet<PathBuf>,
+    pub show_refresh_confirm: bool,
 }
 
 #[derive(Debug, Clone)]
@@ -77,6 +78,7 @@ impl AppState {
             visual_mode: false,
             visual_anchor: 0,
             saved_expanded_dirs: HashSet::new(),
+            show_refresh_confirm: false,
         }
     }