📦 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/fork-ts-checker-webpack-plugin/lib/eslint-reporter/issue/EsLintIssueFactory.d.ts

@@ -0,0 +1,4 @@
+import { Issue } from '../../issue';
+import { LintResult } from '../types/eslint';
+declare function createIssuesFromEsLintResults(results: LintResult[]): Issue[];
+export { createIssuesFromEsLintResults };

frontend/node_modules/fork-ts-checker-webpack-plugin/lib/eslint-reporter/issue/EsLintIssueFactory.js

@@ -0,0 +1,32 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+function createIssueFromEsLintMessage(filePath, message) {
+    let location;
+    if (message.line) {
+        location = {
+            start: {
+                line: message.line,
+                column: message.column,
+            },
+            end: {
+                line: message.endLine || message.line,
+                column: message.endColumn || message.column,
+            },
+        };
+    }
+    return {
+        origin: 'eslint',
+        code: message.ruleId ? String(message.ruleId) : '[unknown]',
+        severity: message.severity === 1 ? 'warning' : 'error',
+        message: message.message,
+        file: filePath,
+        location,
+    };
+}
+function createIssuesFromEsLintResults(results) {
+    return results.reduce((messages, result) => [
+        ...messages,
+        ...result.messages.map((message) => createIssueFromEsLintMessage(result.filePath, message)),
+    ], []);
+}
+exports.createIssuesFromEsLintResults = createIssuesFromEsLintResults;