📦 添加虚拟环境和启动脚本

新增:
- backend/venv/ - Python 虚拟环境
- backend/start.sh - 启动脚本（使用虚拟环境）
- backend/requirements.txt - 依赖列表
- .gitignore - 忽略虚拟环境和缓存文件

说明:
- 每个项目使用独立虚拟环境
- 避免依赖冲突
- 启动脚本自动创建和激活虚拟环境

frontend/node_modules/eslint-plugin-import/docs/rules/no-named-as-default.md

@@ -0,0 +1,53 @@
+# import/no-named-as-default
+
+⚠️ This rule _warns_ in the following configs: ☑️ `recommended`, 🚸 `warnings`.
+
+<!-- end auto-generated rule header -->
+
+Reports use of an exported name as the locally imported name of a default export.
+
+Rationale: using an exported name as the name of the default export is likely...
+
+ - _misleading_: others familiar with `foo.js` probably expect the name to be `foo`
+ - _a mistake_: only needed to import `bar` and forgot the brackets (the case that is prompting this)
+
+## Rule Details
+
+Given:
+
+```js
+// foo.js
+export default 'foo';
+export const bar = 'baz';
+```
+
+...this would be valid:
+
+```js
+import foo from './foo.js';
+```
+
+...and this would be reported:
+
+```js
+// message: Using exported name 'bar' as identifier for default export.
+import bar from './foo.js';
+```
+
+For post-ES2015 `export` extensions, this also prevents exporting the default from a referenced module as a name within that module, for the same reasons:
+
+```js
+// valid:
+export foo from './foo.js';
+
+// message: Using exported name 'bar' as identifier for default export.
+export bar from './foo.js';
+```
+
+## Further Reading
+
+ - ECMAScript Proposal: [export ns from]
+ - ECMAScript Proposal: [export default from]
+
+[export ns from]: https://github.com/leebyron/ecmascript-export-ns-from
+[export default from]: https://github.com/leebyron/ecmascript-export-default-from