feat(nav): 底部导航改为首页推荐追剧我的

lib/core/theme/app_colors.dart

@@ -69,6 +69,11 @@ abstract final class AppColors {
   /// 底部导航底色。
   static const bar = ink;
 
+  /// 底部导航专用：纯黑背景、选中白、未选中灰与轻分割线。
+  static const navBackground = Color(0xFF000000);
+  static const navSelected = Color(0xFFFFFFFF);
+  static const navDivider = Color(0xFF1C1C1E);
+
   /// 卡片阴影（深色几乎不用阴影）。
   static const cardShadow = Color(0x00000000);
 
@@ -121,7 +126,7 @@ abstract final class AppColors {
   static const badgeBeige = raised;
 
   /// 导航未选中。
-  static const navUnselected = muted;
+  static const navUnselected = Color(0xFF8A8A8E);
 
   /// 播放器次要文字。
   static const playerMuted = Color(0xA3FFFFFF);

lib/core/theme/app_dimens.dart

@@ -36,7 +36,7 @@ abstract final class AppDimens {
   static const double previewCardTitle = 13;
   static const double previewSectionTitle = 14;
   static const double chipFont = 10;
-  static const double navLabel = 12;
+  static const double navLabel = 11;
 
   static const double buttonHeight = 48;
   static const double primaryButtonHeight = 52;

lib/core/theme/app_theme.dart

@@ -193,8 +193,8 @@ abstract final class AppTheme {
         ),
       ),
       bottomNavigationBarTheme: const BottomNavigationBarThemeData(
-        backgroundColor: AppColors.bar,
-        selectedItemColor: AppColors.blue,
+        backgroundColor: AppColors.navBackground,
+        selectedItemColor: AppColors.navSelected,
         unselectedItemColor: AppColors.navUnselected,
         elevation: 0,
         type: BottomNavigationBarType.fixed,