refactor: ♻️ 演示界面统一至demo下，精简删除demo目录即可

Former-commit-id: cef5e36eb0e60299d1a72b9a12c9ea8d93a77244

src/views/demo/table/dynamic-table/index.vue

@@ -0,0 +1,24 @@
+<template>
+  <div class="app-container">
+    <div style="margin: 0 0 5px 20px">
+      Fixed header, sorted by header order,
+    </div>
+    <fixed-thead />
+
+    <div style="margin: 30px 0 5px 20px">
+      Not fixed header, sorted by click order
+    </div>
+    <unfixed-thead />
+  </div>
+</template>
+
+<script setup lang="ts">
+import FixedThead from "./components/FixedThead.vue";
+import UnfixedThead from "./components/UnfixedThead.vue";
+
+defineOptions({
+  // eslint-disable-next-line
+  name: "DynamicTable",
+  inheritAttrs: false,
+});
+</script>