feat(chat,board): file/image attachments on chat, board threads and comments

チャット・掲示板(スレッド/コメント)へファイル/画像添付を追加。

- lib/db/migrations/002_attachments.sql: attachments テーブル + file_assets.source 列
- repositories/AttachmentRepository + services/AttachmentService: 添付紐付け(プロジェクト/アップロード者チェック)
- FileStorageService.uploadForAttachment: 通知/SSE/アクティビティを行わない添付専用アップロード(source='attachment')
- ChatService/BoardService: fileIds 受理・添付紐付け・履歴/詳細表示・削除クリーンアップ(トランザクション)
- API: POST /attachments + chat/board の fileIds 受理
- UI: AttachmentList(画像サムネイル+Lightbox/ダウンロード) + AttachmentPicker(複数アップロード・送信中は送信不可) をチャット/スレッド/コメントに統合
- 添付ファイルは既存の /api/files/[fileId]/download(権限チェック済)で配信

services/ChatService.ts

@@ -6,15 +6,21 @@ import type { Paginated } from '@/repositories/ChatRepository';
 import { ProjectMemberRepository } from '@/repositories/ProjectMemberRepository';
 import { UserRepository } from '@/repositories/UserRepository';
 import { NotificationService } from '@/services/NotificationService';
+import { AttachmentService } from '@/services/AttachmentService';
 import { SseHub } from '@/lib/sse/hub';
+import type { SqliteDatabase } from '@/lib/db/sqlite';
 import { ForbiddenError, NotFoundError, ValidationError } from '@/lib/errors';
-import type { ChatMessage } from '@/lib/types';
+import type {
+  AttachmentView,
+  ChatMessage,
+  ChatMessageWithAttachments,
+} from '@/lib/types';
 
 const MENTION_RE = /@([^\s@]+@[^\s@]+\.[^\s@]+)/g;
 
 /**
  * チャットの業務ロジックを担うService。
- * 権限チェック、メッセージ送信/編集/削除、メンション通知、SSE配信を行う。
+ * 権限チェック、メッセージ送信/編集/削除、メンション通知、添付ファイル紐付け、SSE配信を行う。
  */
 export class ChatService {
   constructor(
@@ -22,27 +28,56 @@ export class ChatService {
     private readonly projectMemberRepository: ProjectMemberRepository,
     private readonly userRepository: UserRepository,
     private readonly notificationService: NotificationService,
-    private readonly sseHub: SseHub
+    private readonly sseHub: SseHub,
+    private readonly attachmentService: AttachmentService,
+    private readonly db: SqliteDatabase
   ) {}
 
   getHistory(
     actorId: number,
     projectId: number,
     opts: ListMessagesOptions = {}
-  ): Paginated<ChatMessage> {
+  ): Paginated<ChatMessageWithAttachments> {
     this.requireMember(projectId, actorId);
-    return this.chatRepository.findMessages(projectId, opts);
+    const page = this.chatRepository.findMessages(projectId, opts);
+    const byTarget = this.indexAttachments(
+      'chat_message',
+      page.items.map((m) => m.id)
+    );
+    return {
+      items: page.items.map((m) => this.withAttachments(m, byTarget.get(m.id))),
+      total: page.total,
+    };
   }
 
-  sendMessage(actorId: number, projectId: number, body: string): ChatMessage {
+  sendMessage(
+    actorId: number,
+    projectId: number,
+    body: string,
+    fileIds?: number[]
+  ): ChatMessageWithAttachments {
     this.requireMember(projectId, actorId);
     if (!body.trim()) {
       throw new ValidationError('メッセージを入力してください', 'body');
     }
-    const message = this.chatRepository.create({
-      projectId,
-      authorId: actorId,
-      body,
+    // メッセージ本体と添付紐付けはトランザクション内で一貫保存する
+    const { message, attachments } = this.db.transaction(() => {
+      const msg = this.chatRepository.create({
+        projectId,
+        authorId: actorId,
+        body,
+      });
+      const atts =
+        fileIds && fileIds.length > 0
+          ? this.attachmentService.attach(
+              actorId,
+              projectId,
+              'chat_message',
+              msg.id,
+              fileIds
+            )
+          : [];
+      return { message: msg, attachments: atts };
     });
 
     // メンション検出(@email) → 通知
@@ -64,11 +99,12 @@ export class ChatService {
       }
     }
 
+    const messageWithAttachments = this.withAttachments(message, attachments);
     this.sseHub.broadcast(projectId, {
       type: 'chat.message.created',
-      data: { projectId, message },
+      data: { projectId, message: messageWithAttachments },
     });
-    return message;
+    return messageWithAttachments;
   }
 
   editMessage(actorId: number, messageId: number, body: string): ChatMessage {
@@ -101,13 +137,38 @@ export class ChatService {
     if (message.authorId !== actorId && role !== 'admin') {
       throw new ForbiddenError('投稿者または管理者のみ削除できます');
     }
-    this.chatRepository.delete(messageId);
+    this.db.transaction(() => {
+      this.chatRepository.delete(messageId);
+      this.attachmentService.detach('chat_message', messageId);
+    });
     this.sseHub.broadcast(message.projectId, {
       type: 'chat.message.deleted',
       data: { projectId: message.projectId, id: messageId },
     });
   }
 
+  private withAttachments(
+    message: ChatMessage,
+    attachments: AttachmentView[] | undefined
+  ): ChatMessageWithAttachments {
+    return { ...message, attachments: attachments ?? [] };
+  }
+
+  private indexAttachments(
+    targetType: 'chat_message',
+    targetIds: number[]
+  ): Map<number, AttachmentView[]> {
+    const map = new Map<number, AttachmentView[]>();
+    if (targetIds.length === 0) return map;
+    const views = this.attachmentService.listViewsBatch(targetType, targetIds);
+    for (const v of views) {
+      const list = map.get(v.targetId) ?? [];
+      list.push(v);
+      map.set(v.targetId, list);
+    }
+    return map;
+  }
+
   private requireMember(projectId: number, actorId: number): void {
     if (!this.projectMemberRepository.isMember(projectId, actorId)) {
       throw new ForbiddenError('プロジェクトに参加していません');