feat(nav): 底部导航图标与文字放大

lib/core/theme/app_dimens.dart

@@ -34,7 +34,7 @@ abstract final class AppDimens {
   static const double previewCardTitle = 13;
   static const double previewSectionTitle = 14;
   static const double chipFont = 10;
-  static const double navLabel = 10;
+  static const double navLabel = 12;
 
   static const double buttonHeight = 48;
   static const double primaryButtonHeight = 52;
@@ -45,8 +45,8 @@ abstract final class AppDimens {
   static const double tapTarget = 44;
   static const double contentHeaderHeight = 46;
 
-  static const double navHeight = 64;
-  static const double navIcon = 20;
+  static const double navHeight = 68;
+  static const double navIcon = 24;
   static const double progressHeight = 3;
   static const double progressRadius = 2;
   static const double progressLineHeight = 3;

lib/core/widgets/app_bottom_nav.dart

@@ -107,7 +107,7 @@ class _NavDestination extends StatelessWidget {
                   color: item.selected ? AppColors.blue : unselectedColor,
                 ),
               ),
-              const SizedBox(height: 2),
+              const SizedBox(height: 3),
               Text(
                 item.label,
                 maxLines: 1,

test/theme/app_dimens_test.dart

@@ -16,11 +16,12 @@ void main() {
     expect(AppDimens.listTitle, 15);
     expect(AppDimens.sectionTitle, 16);
     expect(AppDimens.pageTitle, 20);
-    expect(AppDimens.navLabel, 10);
+    expect(AppDimens.navLabel, 12);
+    expect(AppDimens.navIcon, 24);
     expect(AppDimens.buttonHeight, 48);
     expect(AppDimens.primaryButtonHeight, 52);
     expect(AppDimens.tapTarget, 44);
-    expect(AppDimens.navHeight, 64);
+    expect(AppDimens.navHeight, 68);
     expect(AppDimens.progressHeight, 3);
   });
 }