style(agent): 优化工作流页面样式

- 移除工作流卡片标题的自定义颜色样式- 优化 Markdown 渲染容器的样式，确保图片自适应- 调整历史记录项弹出框的样式，使其背景透明无圆角

src/views/agent/work-flow/style.scss

@@ -299,17 +299,15 @@
 
       .res {
         flex: 1 1 0;
-        align-self: stretch;
         padding: 32px;
         flex-direction: column;
         justify-content: center;
         align-items: center;
         gap: 32px;
         display: inline-flex;
-        .markdown-container {
-          max-width: 100%;
-          overflow-x: auto;
-          word-wrap: break-word;
+        :deep(.markdown-container img) {
+          max-width: 100% !important;
+          max-height: auto !important;
         }
       }
     }
@@ -343,7 +341,8 @@
     justify-content: flex-start;
     align-items: center;
     gap: 8px;
-
+    border-radius: 0;
+    background-color: transparent;
     &:hover {
       background: var(--BG-200, #F2F3F5);
     }