docs: freeze YuXinGu lexicon, journey, and P1 engineering sources

Establish product language contract, user journey with dual growth engines,
ERD/OpenAPI/Go boundaries, and H5 routes (/profile, /portrait, /relation,
/membership) before P1 implementation.

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

apps/user-h5/src/pages/PortraitPage.vue

@@ -0,0 +1,32 @@
+<template>
+  <main class="page">
+    <button class="back" type="button" @click="$router.back()">← 返回</button>
+    <h1>个人画像</h1>
+    <p class="sub" v-if="y">生日：{{ y }}-{{ m }}-{{ d }}</p>
+    <div class="card">
+      基础画像将由 API 生成。免费可见基础结论；完整分析为「深度版」或会员权益（见 PRD）。
+    </div>
+    <p class="disc">
+      本内容为自我探索与生活方式参考，不构成医疗建议，亦非占卜预测。
+    </p>
+  </main>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'
+import { useRoute } from 'vue-router'
+
+const route = useRoute()
+const y = computed(() => String(route.query.y || ''))
+const m = computed(() => String(route.query.m || ''))
+const d = computed(() => String(route.query.d || ''))
+</script>
+
+<style scoped>
+.page{padding:16px}
+.back{border:none;background:#fff;border-radius:10px;padding:8px 12px;margin-bottom:12px}
+h1{font-size:22px}
+.sub{color:var(--yxg-sub);margin:8px 0 14px;font-size:13px}
+.card{background:#fff;border-radius:16px;padding:18px;font-size:14px;line-height:1.7;color:#555}
+.disc{font-size:11px;color:#bbb;margin-top:16px;line-height:1.5}
+</style>