chore: seal Design Vision v1 and monorepo scaffold

Archive the differentiated YuXinGu product docs, AI engineering system,
design contract, and Go/Vue scaffold. Next execution prioritizes Cece-parity
over early innovation (see .ai/product/STRATEGY.md).

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/user-h5/src/App.vue

@@ -0,0 +1,15 @@
+<template>
+  <div class="app-shell">
+    <router-view />
+    <TabBar v-if="showTab" />
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'
+import { useRoute } from 'vue-router'
+import TabBar from './components/TabBar.vue'
+
+const route = useRoute()
+const showTab = computed(() => route.meta.tab !== false)
+</script>