fix: N1-N3 — crypto 顶层导入 + 移除冗余 AbortController + _def 重命名

- N1: require('crypto') 内联 → import * as crypto 顶层导入
- N2: 移除 Engine 内未连接的 AbortController（timeout 委托给 AiGatewayService）
- N3: writeUsageLog 的 _def 参数 → definition

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

src/modules/ai-job/ai-job-execution-engine.ts

@@ -1,4 +1,5 @@
 import { Injectable, Logger } from '@nestjs/common';
+import * as crypto from 'crypto';
 import { AiGatewayService } from '../ai/gateway/ai-gateway.service';
 import { AiJobLifecycleRepository } from './ai-job-lifecycle.repository';
 import { JobDefinitionRegistry } from './job-definition-registry';
@@ -142,13 +143,7 @@ export class AiJobExecutionEngineImpl implements AiJobExecutionEngine {
         snapshot = snap.content;
       }
 
-      // 7. Provider timeout via AbortController
-      const controller = new AbortController();
-      const timeoutMs = def.execution.timeoutMs || 30000;
-      const timeoutId = setTimeout(() => controller.abort(), timeoutMs);
-
-      try {
-        // 8. 取消检查（Provider 调用前）
+      // 7. 取消检查（Provider 调用前）
       const currentJob = await this.prisma.aiJob.findUnique({
         where: { id: aiJobId },
         select: { cancelRequestedAt: true },
@@ -161,7 +156,10 @@ export class AiJobExecutionEngineImpl implements AiJobExecutionEngine {
       await context.updateProgress(30);
 
       // ── EXECUTE ──
-        // 9. 调用 AiGatewayService（不直接导入 Provider SDK）
+      // 8. 调用 AiGatewayService（不直接导入 Provider SDK）
+      //    timeout 通过 timeoutMs 参数委托给 AiGatewayService 内部的 AbortController
+      const timeoutMs = def.execution.timeoutMs || 30000;
+      try {
         const response = await this.aiGateway.generate(
           {
             userId: job.userId,
@@ -169,15 +167,13 @@ export class AiJobExecutionEngineImpl implements AiJobExecutionEngine {
             tier: def.model.modelTier as any,
             promptKey: def.prompt.promptKey,
             promptVersion: def.prompt.promptVersion,
-            messages: [], // Snapshot content 应通过 promptTemplate 渲染，此处由 AiGateway 处理
+            messages: [],
             maxTokens: def.model.maxTokens,
-            outputSchema: undefined, // 由 AiGateway 的 parseJson 处理
+            outputSchema: undefined,
           },
           timeoutMs,
         );
 
-        clearTimeout(timeoutId);
-
         await context.updateProgress(70);
 
         // 10. 取消检查（Projector 前）
@@ -203,19 +199,17 @@ export class AiJobExecutionEngineImpl implements AiJobExecutionEngine {
         await context.updateProgress(90);
 
         // ── COMPLETE ──
-        // 11. Usage logging
+        // 9. Usage logging
         await this.writeUsageLog(job.userId, aiJobId, def, response, lockedJob.attemptCount || 0).catch((err) => {
           this.logger.error(`Usage log failed for job=${aiJobId}: ${err.message}`);
         });
 
-        // 12. 标记成功
+        // 10. 标记成功
         await this.lifecycleRepo.markSucceeded(aiJobId);
 
         await context.updateProgress(100);
         this.logger.log(`Job ${aiJobId} (${job.jobType}) completed successfully`);
       } catch (execErr: any) {
-        clearTimeout(timeoutId);
-
         // 取消检查
         if (execErr?.message?.includes('cancelled')) {
           await this.lifecycleRepo.markCancelled(aiJobId);
@@ -282,14 +276,13 @@ export class AiJobExecutionEngineImpl implements AiJobExecutionEngine {
   }
 
   private computeHash(content: string): string {
-    const crypto = require('crypto');
     return crypto.createHash('sha256').update(content).digest('hex').substring(0, 16);
   }
 
   private async writeUsageLog(
     userId: string,
     jobId: string,
-    _def: any,
+    definition: any,
     response: any,
     attemptNo: number,
   ): Promise<void> {
@@ -300,8 +293,8 @@ export class AiJobExecutionEngineImpl implements AiJobExecutionEngine {
         provider: response?.usage?.provider || 'deepseek',
         model: response?.usage?.model || 'deepseek-chat',
         tier: 'primary',
-        promptKey: _def?.prompt?.promptKey || 'unknown',
-        promptVersion: _def?.prompt?.promptVersion || 'unknown',
+        promptKey: definition?.prompt?.promptKey || 'unknown',
+        promptVersion: definition?.prompt?.promptVersion || 'unknown',
         inputTokens: response?.usage?.inputTokens || 0,
         outputTokens: response?.usage?.outputTokens || 0,
         estimatedCost: response?.usage?.estimatedCost || 0,