v4.3 安全修复+代码质量+测试体系+护城河验证

## 安全修复 (5项)
- CRITICAL JWT 硬编码 fallback（jwt.strategy / app.module / user.module）
- HIGH seed_admin.js MongoDB 凭据泄漏
- MEDIUM 邮箱验证码泄漏
- MEDIUM 支付订单查询 IDOR
- MEDIUM 管理后台 NoSQL 注入

## 代码质量 (14处)
- console.log→Logger（user.service.ts）
- as any 类型化（11处跨7个文件）
- Schema 联合类型修复（progress.schema）
- Module 依赖缺失修复（progress.module）

## 测试体系 (61项)
- 后端单元测试 Jest（43项）：BenchmarkService/UserService/PaymentController
- 后端集成测试 Supertest（11项）：API 认证/支付/进度/管理
- 前端单元测试 Vitest（7项）：配置文件/API端点
- 浏览器自动化 Playwright（7项）：API smoke test
- 覆盖率报告 + e2e 配置

## 护城河 P0-P5 启动验证通过 + 编译通过

backend/src/modules/contribution/contribution.controller.ts

@@ -1,17 +1,21 @@
-import { Controller, Post, Get, Body, Param, UseGuards } from '@nestjs/common'
+import { Controller, Post, Get, Body, Param, UseGuards, Logger } from '@nestjs/common'
 import { InjectModel } from '@nestjs/mongoose'
 import { Model } from 'mongoose'
 import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard'
 import { CurrentUser } from '../../common/decorators/current-user.decorator'
+import { AiService } from '../ai/ai.service'
 import { Contribution, ContributionDocument } from '../schemas/contribution.schema'
 import { CompanyBank, CompanyBankDocument } from '../schemas/company-bank.schema'
 
 @Controller('contribution')
 @UseGuards(JwtAuthGuard)
 export class ContributionController {
+  private readonly logger = new Logger(ContributionController.name)
+
   constructor(
     @InjectModel(Contribution.name) private contributionModel: Model<ContributionDocument>,
     @InjectModel(CompanyBank.name) private companyBankModel: Model<CompanyBankDocument>,
+    private readonly aiService: AiService,
   ) {}
 
   @Post()
@@ -39,6 +43,11 @@ export class ContributionController {
       verified: false,
     })
 
+    // Async AI processing (non-blocking)
+    this.aiProcessContribution(contribution, body).catch(e => {
+      this.logger.error(`AI processing failed for contribution ${contribution._id}: ${e.message}`)
+    })
+
     // Update company bank
     if (body.questions && body.questions.length > 0) {
       let bank = await this.companyBankModel.findOne({
@@ -69,7 +78,6 @@ export class ContributionController {
             tags: body.tags || [],
           })
         } else {
-          // Increment frequency
           const existing = bank.questions.find(eq => eq.content === q)
           if (existing) existing.frequency += 1
         }
@@ -79,13 +87,70 @@ export class ContributionController {
     }
 
     return {
-      id: (contribution as any)._id.toString(),
+      id: contribution._id.toString(),
       company: contribution.company,
       position: contribution.position,
       message: '感谢你的分享！你的面经将帮助更多同学准备面试',
     }
   }
 
+  private async aiProcessContribution(contribution: ContributionDocument, body: any) {
+    const prompt = `你是一个面试题分析专家。请分析以下面经内容，返回 JSON（不要 Markdown 包裹）：
+
+公司: ${body.company}
+岗位: ${body.position}
+轮次: ${body.rounds || '未说明'}
+面试题: ${(body.questions || []).join('\n')}
+面试经验: ${body.experience || ''}
+用户标签: ${(body.tags || []).join(', ')}
+
+请返回严格 JSON:
+{
+  "structuredQuestions": [
+    {
+      "content": "原题",
+      "type": "技术题|行为题|场景题|算法题|系统设计题|HR题",
+      "difficulty": "easy|medium|hard",
+      "referenceAnswer": "参考答案",
+      "tags": ["标签1", "标签2"]
+    }
+  ],
+  "aiSummary": "面试总结，包含难度评估、重点方向、准备建议（50字以内）"
+}`
+
+    const result = await this.aiService.call({ systemPrompt: prompt, userMessage: '请分析以上面经', maxTokens: 3000 })
+    const parsed = JSON.parse(result.replace(/```json\s*|\s*```/g, '').trim())
+
+    await this.contributionModel.findByIdAndUpdate(contribution._id, {
+      $set: {
+        aiProcessed: true,
+        structuredQuestions: parsed.structuredQuestions || [],
+        aiSummary: parsed.aiSummary || '',
+      },
+    }).exec()
+
+    // Update company bank with structured data
+    if (parsed.structuredQuestions?.length > 0) {
+      const bank = await this.companyBankModel.findOne({
+        company: body.company,
+        position: body.position,
+      }).exec()
+
+      if (bank) {
+        for (const sq of parsed.structuredQuestions) {
+          const existing = bank.questions.find(eq => eq.content === sq.content)
+          if (existing) {
+            existing.type = sq.type || existing.type
+            existing.difficulty = sq.difficulty || existing.difficulty
+            existing.referenceAnswer = sq.referenceAnswer || existing.referenceAnswer
+            if (sq.tags) existing.tags = [...new Set([...existing.tags, ...sq.tags])]
+          }
+        }
+        await bank.save()
+      }
+    }
+  }
+
   @Get('company/:company/position/:position')
   async getBank(@Param('company') company: string, @Param('position') position: string) {
     const bank = await this.companyBankModel.findOne({ company, position }).exec()