Add attachments to comments

- CommentAttachment link table (comment <-> file) + migration
- fileIds in create/update comment; update replaces the whole set,
  synced in one transaction with the comment
- CommentDto.attachments; empty for deleted comments
- Soft delete drops attachments so GC can collect the files
- Max 10 files per comment, ordered by upload time (uuid v7)
- Registers comments as a file owner
- Rename CommentAuthorExpanderService -> CommentExpanderService
  (expands authors and files)

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

src/modules/comment/comment.module.ts

@@ -2,6 +2,7 @@ import { Module } from '@nestjs/common';
 import { PrismaModule } from '../../common/prisma-adapter/prisma.module.js';
 import { IssueModule } from '../issue/issue.module.js';
 import { UserModule } from '../user/user.module.js';
+import { FileModule } from '../file/file.module.js';
 import { COMMENT_REPOSITORY } from './domain/repositories/comment.repository.interface.js';
 import { CommentPrismaRepository } from './infrastructure/persistence/prisma/repositories/comment.prisma-repository.js';
 import { CommentController } from './presentation/controllers/comment.controller.js';
@@ -11,11 +12,12 @@ import { UpdateCommentUseCase } from './application/use-cases/update-comment/upd
 import { DeleteCommentUseCase } from './application/use-cases/delete-comment/delete-comment.use-case.js';
 import { WatchIssueCommentsUseCase } from './application/use-cases/watch-issue-comments/watch-issue-comments.use-case.js';
 import { CommentAccessService } from './application/services/comment-access.service.js';
-import { CommentAuthorExpanderService } from './application/services/comment-author-expander.service.js';
+import { CommentExpanderService } from './application/services/comment-expander.service.js';
 import { CommentEventsService } from './application/services/comment-events.service.js';
+import { CommentAttachmentFileOwnerService } from './application/services/comment-attachment-file-owner.service.js';
 
 @Module({
-  imports: [PrismaModule, IssueModule, UserModule],
+  imports: [PrismaModule, IssueModule, UserModule, FileModule],
   controllers: [CommentController],
   providers: [
     CreateCommentUseCase,
@@ -24,8 +26,9 @@ import { CommentEventsService } from './application/services/comment-events.serv
     DeleteCommentUseCase,
     WatchIssueCommentsUseCase,
     CommentAccessService,
-    CommentAuthorExpanderService,
+    CommentExpanderService,
     CommentEventsService,
+    CommentAttachmentFileOwnerService,
     {
       // Domain видит только интерфейс ICommentRepository,
       // конкретную реализацию (Prisma) подставляет DI-контейнер здесь