feat(flutter): 重构四 Tab 与浏览页

lib/core/theme/app_dimens.dart

@@ -42,6 +42,8 @@ abstract final class AppDimens {
   static const double buttonMedium = 40;
   static const double buttonLarge = 44;
   static const double tapTarget = 44;
+  static const double contentHeaderHeight = 46;
+  static const double filterChipHeight = 34;
 
   static const double navHeight = 54;
   static const double navIcon = 17;
@@ -58,4 +60,12 @@ abstract final class AppDimens {
   static const double accountLabel = 11;
 
   static const double watchPlaceholderHeight = 114;
+  static const double heroBannerHeight = 176;
+  static const double continueCoverWidth = 52;
+  static const double continueCoverHeight = 66;
+
+  static const double cardMeta = 9;
+  static const double cardViews = 9;
+  static const double createIcon = 22;
+  static const double createArrow = 18;
 }

lib/core/widgets/app_bottom_nav.dart

@@ -26,7 +26,7 @@ class AppBottomNavItem {
   final bool selected;
 }
 
-/// Shared 3-tab navigation used by all root tabs and the player fallback.
+/// Shared bottom navigation used by the root shell and standalone tabs.
 class AppBottomNav extends StatelessWidget {
   const AppBottomNav({
     super.key,

lib/core/widgets/remote_image.dart

@@ -1,3 +1,5 @@
+// Author: fruit.com.cn
+
 import 'package:flutter/material.dart';
 
 import '../config/app_config.dart';
@@ -13,6 +15,7 @@ class RemoteImage extends StatelessWidget {
     this.fit = BoxFit.cover,
     this.showFallbackIcon = false,
     this.fallbackIconKey,
+    this.fallbackAspectRatio,
   });
 
   final String path;
@@ -21,6 +24,7 @@ class RemoteImage extends StatelessWidget {
   final BoxFit fit;
   final bool showFallbackIcon;
   final Key? fallbackIconKey;
+  final double? fallbackAspectRatio;
 
   @override
   Widget build(BuildContext context) {
@@ -40,7 +44,7 @@ class RemoteImage extends StatelessWidget {
   }
 
   Widget _fallback() {
-    return Container(
+    final fallback = Container(
       width: width,
       height: height,
       color: AppColors.bar,
@@ -54,5 +58,8 @@ class RemoteImage extends StatelessWidget {
             )
           : null,
     );
+    final ratio = fallbackAspectRatio;
+    if (ratio == null) return fallback;
+    return AspectRatio(aspectRatio: ratio, child: fallback);
   }
 }