fix: 移除所有弹框遮罩层点击关闭 — 防止输入时误触关闭

涉及文件 (12处):
- InstancePage.tsx: 添加数据源弹框
- UsersPage.tsx: 新建/编辑/重置密码/详情弹框 (4处)
- RolesPage.tsx: 克隆角色弹框
- InstanceGroupPage.tsx: 新建/编辑/关联实例/关联用户弹框 (4处)
- SlowQueryPage.tsx: 查询对比弹框
- RedisDetailPage.tsx: 键详情/新增键弹框 (2处)

改动: 遮罩层div移除onClick，只能通过X按钮或取消按钮关闭

frontend/src/pages/InstancePage.tsx

@@ -991,7 +991,7 @@ function CreateInstanceForm({ defaultType, onCancel, onCreated }: {
   const labelCls = 'block text-sm font-medium mb-1.5';
 
   return (
-    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 backdrop-blur-sm" onClick={onCancel}>
+    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 backdrop-blur-sm">
       <div
         className="bg-[var(--dg-bg-secondary)] rounded-xl shadow-2xl w-full max-w-2xl max-h-[90vh] overflow-y-auto"
         onClick={e => e.stopPropagation()}