Add issue attachments

- IssueAttachment link table (issue <-> file) + migration
- GET/POST /issues/:issueId/attachments, DELETE .../attachments/:fileId
- Only own uploaded files can be attached; attach is idempotent
- Registers issues as a file owner: attached files stay visible to issue
  participants and are not collected by GC
- IssueDetail.attachments GraphQL field via @ResolveField, issue module untouched

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/modules/issue-attachment/application/services/issue-attachment-expander.service.spec.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it, vi } from 'vitest';
+import type { GetFilesUseCase } from '../../../file/application/use-cases/get-files/get-files.use-case.js';
+import { IssueAttachmentExpanderService } from './issue-attachment-expander.service.js';
+import { buildAttachment, buildFileDto } from '../use-cases/test-helpers.js';
+
+describe('IssueAttachmentExpanderService', () => {
+  it('expands attachments into files and skips files deleted in between', async () => {
+    const getFiles = { execute: vi.fn().mockResolvedValue([buildFileDto('a')]) } as unknown as GetFilesUseCase;
+    const expander = new IssueAttachmentExpanderService(getFiles);
+
+    const list = await expander.expandAll([buildAttachment({ fileId: 'a' }), buildAttachment({ fileId: 'gone' })]);
+
+    expect(list).toEqual([{ issueId: 1, file: buildFileDto('a'), attachedAt: new Date('2026-01-02T00:00:00.000Z') }]);
+  });
+});

src/modules/issue-attachment/application/services/issue-attachment-expander.service.ts

@@ -0,0 +1,24 @@
+import { Injectable } from '@nestjs/common';
+import { IssueAttachment } from '../../domain/entities/issue-attachment.entity.js';
+import { IssueAttachmentDto } from '../dto/issue-attachment.dto.js';
+import { GetFilesUseCase } from '../../../file/application/use-cases/get-files/get-files.use-case.js';
+import { GetFilesQuery } from '../../../file/application/use-cases/get-files/get-files.query.js';
+
+/** Раскрывает вложения в метаданные файлов из file-модуля */
+@Injectable()
+export class IssueAttachmentExpanderService {
+  constructor(private readonly getFilesUseCase: GetFilesUseCase) {}
+
+  async expandAll(attachments: IssueAttachment[]): Promise<IssueAttachmentDto[]> {
+    if (attachments.length === 0) return [];
+
+    const files = await this.getFilesUseCase.execute(new GetFilesQuery(attachments.map((a) => a.fileId)));
+    const filesById = new Map(files.map((file) => [file.id, file]));
+
+    // Файл могли удалить между запросами — такое вложение просто не показываем
+    return attachments.flatMap((attachment) => {
+      const file = filesById.get(attachment.fileId);
+      return file ? [{ issueId: attachment.issueId, file, attachedAt: attachment.createdAt }] : [];
+    });
+  }
+}

src/modules/issue-attachment/application/services/issue-attachment-file-owner.service.spec.ts

@@ -0,0 +1,43 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import type { IIssueAttachmentRepository } from '../../domain/repositories/issue-attachment.repository.interface.js';
+import type { IIssueRepository } from '../../../issue/domain/repositories/issue.repository.interface.js';
+import { FileOwnerRegistry } from '../../../file/application/services/file-owner.registry.js';
+import { IssueAttachmentFileOwnerService } from './issue-attachment-file-owner.service.js';
+import { buildIssue, mockAttachmentRepository, mockIssueRepository } from '../use-cases/test-helpers.js';
+
+describe('IssueAttachmentFileOwnerService', () => {
+  let attachmentRepository: IIssueAttachmentRepository;
+  let issueRepository: IIssueRepository;
+  let registry: FileOwnerRegistry;
+  let owner: IssueAttachmentFileOwnerService;
+
+  beforeEach(() => {
+    attachmentRepository = mockAttachmentRepository();
+    issueRepository = mockIssueRepository();
+    registry = new FileOwnerRegistry();
+    owner = new IssueAttachmentFileOwnerService(attachmentRepository, issueRepository, registry);
+    owner.onModuleInit();
+  });
+
+  it('registers itself, so GC keeps attached files', async () => {
+    vi.mocked(attachmentRepository.findReferencedFileIds).mockResolvedValue(['a']);
+
+    expect(await registry.findReferenced(['a', 'b'])).toEqual(new Set(['a']));
+  });
+
+  it('makes a file visible to users who see one of its issues', async () => {
+    vi.mocked(attachmentRepository.findIssueIdsByFile).mockResolvedValue([1, 2]);
+    vi.mocked(issueRepository.findById).mockImplementation(async (id: number) => (id === 2 ? buildIssue() : null));
+
+    expect(await registry.isVisibleThroughAnyOwner('file-1', 'user-2')).toBe(true);
+    expect(issueRepository.findById).toHaveBeenCalledWith(1, 'user-2');
+    expect(issueRepository.findById).toHaveBeenCalledWith(2, 'user-2');
+  });
+
+  it('hides a file whose issues are all invisible', async () => {
+    vi.mocked(attachmentRepository.findIssueIdsByFile).mockResolvedValue([1]);
+    vi.mocked(issueRepository.findById).mockResolvedValue(null);
+
+    expect(await owner.isVisibleThrough('file-1', 'user-3')).toBe(false);
+  });
+});

src/modules/issue-attachment/application/services/issue-attachment-file-owner.service.ts

@@ -0,0 +1,51 @@
+import { Inject, Injectable, type OnModuleInit } from '@nestjs/common';
+import {
+  ISSUE_ATTACHMENT_REPOSITORY,
+  type IIssueAttachmentRepository,
+} from '../../domain/repositories/issue-attachment.repository.interface.js';
+import {
+  ISSUE_REPOSITORY,
+  type IIssueRepository,
+} from '../../../issue/domain/repositories/issue.repository.interface.js';
+import { FileOwnerRegistry, type FileOwner } from '../../../file/application/services/file-owner.registry.js';
+
+/**
+ * Регистрирует задачи как владельца файлов: без этого GC file-модуля
+ * считал бы прикреплённые файлы сиротами и удалял их.
+ */
+@Injectable()
+export class IssueAttachmentFileOwnerService implements FileOwner, OnModuleInit {
+  readonly name = 'issue';
+
+  constructor(
+    @Inject(ISSUE_ATTACHMENT_REPOSITORY)
+    private readonly attachmentRepository: IIssueAttachmentRepository,
+    @Inject(ISSUE_REPOSITORY)
+    private readonly issueRepository: IIssueRepository,
+    private readonly fileOwners: FileOwnerRegistry,
+  ) {}
+
+  onModuleInit(): void {
+    this.fileOwners.register(this);
+  }
+
+  findReferenced(fileIds: string[]): Promise<string[]> {
+    return this.attachmentRepository.findReferencedFileIds(fileIds);
+  }
+
+  /**
+   * Файл виден, если видна хоть одна задача, к которой он прикреплён.
+   * Видимость проверяем через IIssueRepository.findById, чтобы правило
+   * (reporter/assignee) жило в одном месте. Обычно файл прикреплён к одной задаче.
+   */
+  async isVisibleThrough(fileId: string, userId: string): Promise<boolean> {
+    const issueIds = await this.attachmentRepository.findIssueIdsByFile(fileId);
+
+    for (const issueId of issueIds) {
+      if (await this.issueRepository.findById(issueId, userId)) {
+        return true;
+      }
+    }
+    return false;
+  }
+}