feat: 优化登录后Dashboard界面和导航组件

- Dashboard: 添加欢迎横幅、数据分区展示、当日利润预估
- Logo: 品牌化设计(渐变背景+图标)
- UserMenu: 现代化胶囊样式+头像
- 卡片悬浮动效、彩色分类边框

USER.md

@@ -0,0 +1,17 @@
+# USER.md - About Your Human
+
+_Learn about the person you're helping. Update this as you go._
+
+- **Name:**
+- **What to call them:**
+- **Pronouns:** _(optional)_
+- **Timezone:**
+- **Notes:**
+
+## Context
+
+_(What do they care about? What projects are they working on? What annoys them? What makes them laugh? Build this over time.)_
+
+---
+
+The more you know, the better you can help. But remember — you're learning about a person, not building a dossier. Respect the difference.