fix(flutter): 去除关注 tab 并加深色首页导航

lib/core/widgets/app_bottom_nav.dart

@@ -26,18 +26,20 @@ class AppBottomNavItem {
   final bool selected;
 }
 
-/// 四槽底部导航，仅做浅色暖橙视觉换肤。
+/// 四槽底部导航：首页 feed 用深色样式，其它页面保持浅色暖橙风格。
 class AppBottomNav extends StatelessWidget {
   const AppBottomNav({
     super.key,
     required this.items,
     this.backgroundColor = AppColors.bar,
     this.barKey,
+    this.dark = false,
   });
 
   final List<AppBottomNavItem> items;
   final Color backgroundColor;
   final Key? barKey;
+  final bool dark;
 
   @override
   Widget build(BuildContext context) {
@@ -50,11 +52,25 @@ class AppBottomNav extends StatelessWidget {
             key: barKey,
             height: AppDimens.navHeight,
             decoration: BoxDecoration(
-              color: backgroundColor.withValues(alpha: 0.95),
-              border: const Border(top: BorderSide(color: AppColors.border)),
+              color: dark
+                  ? const Color(0xE6000000)
+                  : backgroundColor.withValues(alpha: 0.95),
+              border: Border(
+                top: BorderSide(
+                  color: dark ? Colors.white12 : AppColors.border,
+                ),
+              ),
             ),
             child: Row(
-              children: [for (final item in items) _NavDestination(item: item)],
+              children: [
+                for (final item in items)
+                  _NavDestination(
+                    item: item,
+                    unselectedColor: dark
+                        ? Colors.white70
+                        : AppColors.navUnselected,
+                  ),
+              ],
             ),
           ),
         ),
@@ -64,9 +80,10 @@ class AppBottomNav extends StatelessWidget {
 }
 
 class _NavDestination extends StatelessWidget {
-  const _NavDestination({required this.item});
+  const _NavDestination({required this.item, required this.unselectedColor});
 
   final AppBottomNavItem item;
+  final Color unselectedColor;
 
   @override
   Widget build(BuildContext context) => Expanded(
@@ -89,9 +106,7 @@ class _NavDestination extends StatelessWidget {
                 child: Icon(
                   item.selected ? item.selectedIcon : item.icon,
                   size: AppDimens.navIcon,
-                  color: item.selected
-                      ? AppColors.blue
-                      : AppColors.navUnselected,
+                  color: item.selected ? AppColors.blue : unselectedColor,
                 ),
               ),
               const SizedBox(height: 2),
@@ -102,9 +117,7 @@ class _NavDestination extends StatelessWidget {
                 style: TextStyle(
                   fontSize: AppDimens.navLabel,
                   fontWeight: item.selected ? FontWeight.w700 : FontWeight.w500,
-                  color: item.selected
-                      ? AppColors.blue
-                      : AppColors.navUnselected,
+                  color: item.selected ? AppColors.blue : unselectedColor,
                   letterSpacing: 0,
                 ),
               ),