📦 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/messages/invalid-rule-options.js

@@ -0,0 +1,17 @@
+"use strict";
+
+const { stringifyValueForError } = require("./shared");
+
+module.exports = function({ ruleId, value }) {
+    return `
+Configuration for rule "${ruleId}" is invalid. Each rule must have a severity ("off", 0, "warn", 1, "error", or 2) and may be followed by additional options for the rule.
+
+You passed '${stringifyValueForError(value, 4)}', which doesn't contain a valid severity.
+
+If you're attempting to configure rule options, perhaps you meant:
+
+    "${ruleId}": ["error", ${stringifyValueForError(value, 8)}]
+
+See https://eslint.org/docs/latest/use/configure/rules#using-configuration-files for configuring rules.
+`.trimStart();
+};