refactor: 重构前端 UI 组件与后端 AgentScope schemas

apps/lib/shared/widgets/link_button.dart

@@ -9,21 +9,25 @@ class LinkButton extends StatelessWidget {
     required this.onTap,
     this.enabled = true,
     this.textAlign = TextAlign.center,
+    this.foregroundColor,
   });
 
   final String text;
   final VoidCallback? onTap;
   final bool enabled;
   final TextAlign textAlign;
+  final Color? foregroundColor;
 
   @override
   Widget build(BuildContext context) {
+    final effectiveColor = foregroundColor ?? AppColors.slate500;
+
     return SizedBox(
       height: 44,
       child: TextButton(
         onPressed: enabled ? onTap : null,
         style: TextButton.styleFrom(
-          foregroundColor: enabled ? AppColors.slate500 : AppColors.slate300,
+          foregroundColor: enabled ? effectiveColor : AppColors.slate300,
           padding: const EdgeInsets.symmetric(
             horizontal: AppSpacing.md,
             vertical: AppSpacing.sm,