Feat: early mouse support

src/services/dict_nav.rs

@@ -8,6 +8,12 @@ pub fn toggle_focus(ui: &mut UiState) {
     };
 }
 
+pub fn select_category(ui: &mut UiState, index: usize) {
+    if index < categories::category_count() {
+        ui.dict_category = index;
+    }
+}
+
 pub fn next_category(ui: &mut UiState) {
     let count = categories::category_count();
     ui.dict_category = (ui.dict_category + 1) % count;