docs: 添加中文文档，新增前端和后端代码

- 新增 README_CN.md 中文文档
- 新增 frontend/ Vue 3 前端项目
- 新增 web/ FastAPI 后端项目

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/.vite/deps/_metadata.json

@@ -0,0 +1,8 @@
+{
+  "hash": "aeb85a64",
+  "configHash": "6a6890cb",
+  "lockfileHash": "e3b0c442",
+  "browserHash": "317b43a0",
+  "optimized": {},
+  "chunks": {}
+}

frontend/.vite/deps/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}