feat: 重构工作流组件，动态加载节点类型，移除旧的侧边栏和背景组件

src/layouts/components/DropzoneBackground.vue

@@ -0,0 +1,12 @@
+<script lang="ts" setup>
+import { Background } from '@vue-flow/background'
+</script>
+
+<template>
+  <div class="dropzone-background">
+    <Background :size="2" :gap="20" pattern-color="#BDBDBD" />
+    <div class="overlay">
+      <slot />
+    </div>
+  </div>
+</template>