fix(ui): 修正卡片正文预留高度，消除底部溢出

lib/core/theme/app_dimens.dart

@@ -189,8 +189,9 @@ abstract final class AppDimens {
   static const double followingAddIconStroke = 1.5;
   static const double followingGridGap = 6;
   static const double followingGridRowGap = 12;
-  // 单行标题 16*1.3 + 间距 6+4 + 副标题约 16 ≈ 47。
-  static const double followingCardTextExtent = 48;
+  // 单行标题 16*1.3=20.8 + 间距 6+4 + 副标题行高约 18.6 ≈ 49.4，留 0.6 余量；
+  // 按 48 估算在副标题行高偏高的字体下会溢出 1~2px。
+  static const double followingCardTextExtent = 50;
   static const double followingSubtitleFont = 12;
   static const double followingSubtitleGap = 4;
   static const double followingProgressHeight = 2;