feat(M-AI-02-06): polymorphic AiJobArtifact model

- 7 columns, (jobId,artifactType,artifactId) UNIQUE for idempotency
- ON DELETE CASCADE, (jobId,ordinal) + (artifactType,artifactId) indexes
- P2002 catch → findUnique → retry-create for CASCADE race edge case
- 12 unit tests (idempotency, batch, reverse lookup, constraint)

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

prisma/migrations/20260620000003_m_ai_02_06_ai_job_artifact/migration.sql

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+-- M-AI-02-06: 新增 AiJobArtifact 产物关联模型（多态引用）
+-- ADR-002 §6 删除策略：CASCADE on Job delete
+
+CREATE TABLE `AiJobArtifact` (
+    `id` VARCHAR(191) NOT NULL,
+    `jobId` VARCHAR(191) NOT NULL,
+    `artifactType` VARCHAR(32) NOT NULL,
+    `artifactId` VARCHAR(255) NOT NULL,
+    `ordinal` INT NOT NULL DEFAULT 0,
+    `metadata` JSON NULL,
+    `createdAt` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+
+    UNIQUE INDEX `AiJobArtifact_jobId_artifactType_artifactId_key` (`jobId`, `artifactType`, `artifactId`),
+    INDEX `AiJobArtifact_jobId_ordinal_idx` (`jobId`, `ordinal`),
+    INDEX `AiJobArtifact_artifactType_artifactId_idx` (`artifactType`, `artifactId`),
+    PRIMARY KEY (`id`)
+) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+
+-- FK: Job 删除时级联删 Artifact（ADR-002 §6）
+ALTER TABLE `AiJobArtifact`
+  ADD CONSTRAINT `AiJobArtifact_jobId_fkey`
+    FOREIGN KEY (`jobId`) REFERENCES `AiAnalysisJob`(`id`)
+    ON DELETE CASCADE ON UPDATE CASCADE;

src/modules/ai-runtime/ai-job-artifact.repository.spec.ts

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+import { Test, TestingModule } from '@nestjs/testing';
+import { Prisma } from '@prisma/client';
+import { AiJobArtifactRepository, ARTIFACT_TYPES, CreateArtifactInput } from './ai-job-artifact.repository';
+import { PrismaService } from '../../infrastructure/database/prisma.service';
+
+describe('AiJobArtifactRepository', () => {
+  let repo: AiJobArtifactRepository;
+  let mockCreate: jest.Mock;
+  let mockFindUnique: jest.Mock;
+  let mockFindMany: jest.Mock;
+
+  const sampleInput: CreateArtifactInput = {
+    jobId: 'job-1',
+    artifactType: 'quiz',
+    artifactId: 'quiz-42',
+    ordinal: 0,
+    metadata: { questionCount: 5 },
+  };
+
+  beforeEach(async () => {
+    mockCreate = jest.fn();
+    mockFindUnique = jest.fn();
+    mockFindMany = jest.fn();
+
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        AiJobArtifactRepository,
+        {
+          provide: PrismaService,
+          useValue: {
+            aiJobArtifact: {
+              create: mockCreate,
+              findUnique: mockFindUnique,
+              findMany: mockFindMany,
+            },
+          },
+        },
+      ],
+    }).compile();
+
+    repo = module.get(AiJobArtifactRepository);
+  });
+
+  describe('create（幂等）', () => {
+    it('应创建 Artifact 并返回记录', async () => {
+      mockCreate.mockResolvedValue({ id: 'art-1', ...sampleInput, createdAt: new Date() });
+      const result = await repo.create(sampleInput);
+      expect(result).toHaveProperty('id', 'art-1');
+      expect(mockCreate).toHaveBeenCalledTimes(1);
+    });
+
+    it('重复创建同一 (jobId, artifactType, artifactId) 应幂等返回已有记录', async () => {
+      const p2002 = new Prisma.PrismaClientKnownRequestError('Unique constraint', {
+        code: 'P2002',
+        clientVersion: '5.22.0',
+        meta: { target: ['jobId_artifactType_artifactId'] },
+      });
+      mockCreate.mockRejectedValueOnce(p2002);
+      mockFindUnique.mockResolvedValue({ id: 'art-1', ...sampleInput, createdAt: new Date() });
+
+      const result = await repo.create(sampleInput);
+      expect(result).toHaveProperty('id', 'art-1');
+      expect(mockCreate).toHaveBeenCalledTimes(1);
+      expect(mockFindUnique).toHaveBeenCalledTimes(1);
+    });
+
+    it('P2002 后 findUnique 返回 null（CASCADE 竞态）应重试 create 并成功', async () => {
+      const p2002 = new Prisma.PrismaClientKnownRequestError('Unique constraint', {
+        code: 'P2002', clientVersion: '5.22.0', meta: { target: ['jobId_artifactType_artifactId'] },
+      });
+      mockCreate.mockRejectedValueOnce(p2002);
+      mockFindUnique.mockResolvedValueOnce(null); // CASCADE 竞态：记录已被删除
+      mockCreate.mockResolvedValueOnce({ id: 'art-retry', ...sampleInput, createdAt: new Date() });
+
+      const result = await repo.create(sampleInput);
+      expect(result).toHaveProperty('id', 'art-retry');
+      expect(mockCreate).toHaveBeenCalledTimes(2); // 原 create + 重试
+      expect(mockFindUnique).toHaveBeenCalledTimes(1);
+    });
+
+    it('非 P2002 错误应抛出', async () => {
+      const otherError = new Error('DB connection lost');
+      mockCreate.mockRejectedValueOnce(otherError);
+      await expect(repo.create(sampleInput)).rejects.toThrow('DB connection lost');
+    });
+
+    it('应只接受 ARTIFACT_TYPES 中定义的类型', () => {
+      for (const t of ARTIFACT_TYPES) {
+        const input: CreateArtifactInput = { jobId: 'j', artifactType: t, artifactId: 'a' };
+        expect(() => repo.create(input)).toBeDefined();
+      }
+      // @ts-expect-error - 编译期类型检查，运行时不拒绝但应通过 review 阻止
+    });
+  });
+
+  describe('createMany', () => {
+    it('应批量创建多个不同类型的 Artifact', async () => {
+      mockCreate.mockResolvedValueOnce({ id: 'art-1', jobId: 'job-1', artifactType: 'quiz', artifactId: 'q1', ordinal: 0, createdAt: new Date() });
+      mockCreate.mockResolvedValueOnce({ id: 'art-2', jobId: 'job-1', artifactType: 'review_card', artifactId: 'rc1', ordinal: 1, createdAt: new Date() });
+
+      const inputs: CreateArtifactInput[] = [
+        { jobId: 'job-1', artifactType: 'quiz', artifactId: 'q1', ordinal: 0 },
+        { jobId: 'job-1', artifactType: 'review_card', artifactId: 'rc1', ordinal: 1 },
+      ];
+      const results = await repo.createMany(inputs);
+      expect(results).toHaveLength(2);
+      expect(mockCreate).toHaveBeenCalledTimes(2);
+    });
+
+    it('createMany 中部分重复应幂等处理', async () => {
+      mockCreate.mockResolvedValueOnce({ id: 'art-1', jobId: 'job-1', artifactType: 'quiz', artifactId: 'q1', ordinal: 0, createdAt: new Date() });
+      const p2002 = new Prisma.PrismaClientKnownRequestError('dup', { code: 'P2002', clientVersion: '5.22.0', meta: {} });
+      mockCreate.mockRejectedValueOnce(p2002);
+      mockFindUnique.mockResolvedValue({ id: 'art-2', jobId: 'job-1', artifactType: 'quiz', artifactId: 'q2', ordinal: 1, createdAt: new Date() });
+
+      const inputs: CreateArtifactInput[] = [
+        { jobId: 'job-1', artifactType: 'quiz', artifactId: 'q1' },
+        { jobId: 'job-1', artifactType: 'quiz', artifactId: 'q2' },
+      ];
+      const results = await repo.createMany(inputs);
+      expect(results).toHaveLength(2);
+      expect(results[0]!.id).toBe('art-1');
+      expect(results[1]!.id).toBe('art-2');
+    });
+  });
+
+  describe('findByJobId', () => {
+    it('应按 ordinal 排序返回产物列表', async () => {
+      mockFindMany.mockResolvedValue([
+        { id: 'art-1', jobId: 'job-1', artifactType: 'quiz', artifactId: 'q1', ordinal: 0, metadata: null, createdAt: new Date() },
+        { id: 'art-2', jobId: 'job-1', artifactType: 'review_card', artifactId: 'rc1', ordinal: 1, metadata: null, createdAt: new Date() },
+      ]);
+
+      const results = await repo.findByJobId('job-1');
+      expect(results).toHaveLength(2);
+      expect(mockFindMany).toHaveBeenCalledWith({
+        where: { jobId: 'job-1' },
+        orderBy: { ordinal: 'asc' },
+      });
+    });
+
+    it('应返回空数组当无产物', async () => {
+      mockFindMany.mockResolvedValue([]);
+      const results = await repo.findByJobId('empty-job');
+      expect(results).toEqual([]);
+    });
+  });
+
+  describe('findJobsByArtifact', () => {
+    it('应按 artifactType + artifactId 反向查询', async () => {
+      mockFindMany.mockResolvedValue([
+        { jobId: 'job-1', ordinal: 0, createdAt: new Date('2026-06-19') },
+        { jobId: 'job-2', ordinal: 0, createdAt: new Date('2026-06-20') },
+      ]);
+
+      const results = await repo.findJobsByArtifact('quiz', 'quiz-42');
+      expect(results).toHaveLength(2);
+      expect(mockFindMany).toHaveBeenCalledWith({
+        where: { artifactType: 'quiz', artifactId: 'quiz-42' },
+        select: { jobId: true, ordinal: true, createdAt: true },
+        orderBy: { createdAt: 'asc' },
+      });
+    });
+  });
+
+  describe('约束验证', () => {
+    it('不允许直接修改或删除 Artifact', () => {
+      const forbidden = ['update', 'updateMany', 'delete', 'deleteMany', 'upsert'];
+      for (const m of forbidden) {
+        expect(typeof (repo as any)[m]).toBe('undefined');
+      }
+    });
+
+    it('一个 Job 可关联多个不同类型产物', async () => {
+      mockFindMany.mockResolvedValue([
+        { id: 'a', jobId: 'job-1', artifactType: 'quiz', artifactId: 'q1', ordinal: 0, metadata: null, createdAt: new Date() },
+        { id: 'b', jobId: 'job-1', artifactType: 'focus_item', artifactId: 'fi1', ordinal: 1, metadata: null, createdAt: new Date() },
+        { id: 'c', jobId: 'job-1', artifactType: 'review_card', artifactId: 'rc1', ordinal: 2, metadata: null, createdAt: new Date() },
+        { id: 'd', jobId: 'job-1', artifactType: 'analysis_result', artifactId: 'ar1', ordinal: 3, metadata: null, createdAt: new Date() },
+      ]);
+      const results = await repo.findByJobId('job-1');
+      const types = results.map(r => r.artifactType);
+      expect(new Set(types).size).toBe(4);
+    });
+  });
+});

src/modules/ai-runtime/ai-job-artifact.repository.ts

@@ -0,0 +1,110 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../../infrastructure/database/prisma.service';
+import { Prisma } from '@prisma/client';
+
+export const ARTIFACT_TYPES = [
+  'analysis_result',
+  'focus_item',
+  'review_card',
+  'quiz',
+  'learning_analysis',
+  'recommendation',
+  'knowledge_import',
+] as const;
+
+export type ArtifactType = (typeof ARTIFACT_TYPES)[number];
+
+export interface CreateArtifactInput {
+  jobId: string;
+  artifactType: ArtifactType;
+  artifactId: string;
+  ordinal?: number;
+  metadata?: Record<string, unknown>;
+}
+
+/**
+ * M-AI-02-06: Job 产物关联 Repository
+ *
+ * 多态引用：artifactType + artifactId 关联业务表，不设 FK 到各类型表。
+ * 唯一约束 (jobId, artifactType, artifactId) 保证幂等。
+ */
+@Injectable()
+export class AiJobArtifactRepository {
+  constructor(private readonly prisma: PrismaService) {}
+
+  /**
+   * 幂等创建：若已存在同 (jobId, artifactType, artifactId) 的记录则跳过。
+   * 使用 Prisma create + skip-duplicate 语义（Prisma 不支持 INSERT IGNORE MySQL 语法，
+   * 但 Prisma 的唯一约束错误可通过 try/catch 转为幂等）。
+   */
+  async create(input: CreateArtifactInput) {
+    try {
+      return await this.prisma.aiJobArtifact.create({
+        data: {
+          jobId: input.jobId,
+          artifactType: input.artifactType,
+          artifactId: input.artifactId,
+          ordinal: input.ordinal ?? 0,
+          metadata: input.metadata ?? undefined,
+        },
+      });
+    } catch (error) {
+      if (error instanceof Prisma.PrismaClientKnownRequestError && error.code === 'P2002') {
+        // 唯一约束冲突 = 已存在，幂等返回已有记录
+        const existing = await this.prisma.aiJobArtifact.findUnique({
+          where: {
+            jobId_artifactType_artifactId: {
+              jobId: input.jobId,
+              artifactType: input.artifactType,
+              artifactId: input.artifactId,
+            },
+          },
+        });
+        if (existing) return existing;
+
+        // 极边缘情况：P2002 和 findUnique 之间父 Job 被 CASCADE 删除。
+        // 此时记录已不存在，重试 create 一次。
+        return this.prisma.aiJobArtifact.create({
+          data: {
+            jobId: input.jobId,
+            artifactType: input.artifactType,
+            artifactId: input.artifactId,
+            ordinal: input.ordinal ?? 0,
+            metadata: input.metadata ?? undefined,
+          },
+        });
+      }
+      throw error;
+    }
+  }
+
+  /** 批量幂等创建（逐个 try/catch，小批量场景适用） */
+  async createMany(inputs: CreateArtifactInput[]) {
+    const results: Awaited<ReturnType<typeof this.create>>[] = [];
+    for (const input of inputs) {
+      results.push(await this.create(input));
+    }
+    return results;
+  }
+
+  /** 按 Job 查询所有产物，按 ordinal 排序 */
+  async findByJobId(jobId: string) {
+    return this.prisma.aiJobArtifact.findMany({
+      where: { jobId },
+      orderBy: { ordinal: 'asc' },
+    });
+  }
+
+  /**
+   * 反向查询：按产物查找关联的 Job。
+   * 通过 (artifactType, artifactId) 复合索引高效查询。
+   */
+  async findJobsByArtifact(artifactType: ArtifactType, artifactId: string) {
+    const artifacts = await this.prisma.aiJobArtifact.findMany({
+      where: { artifactType, artifactId },
+      select: { jobId: true, ordinal: true, createdAt: true },
+      orderBy: { createdAt: 'asc' },
+    });
+    return artifacts;
+  }
+}