refactor: apply SessionManager to all agents

- domain-agent: use DomainSessionManager (handles target_domain)
- deposit-agent: use SessionManager<DepositSession>
- troubleshoot-agent: use SessionManager<TroubleshootSession>
- server-agent: use ServerSessionManager (handles last_recommendation)
- Remove ~760 lines of duplicated session CRUD code
- Use centralized constants from agent-config.ts
- Import OpenAI types from types.ts instead of local definitions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/agents/server-agent.ts

@@ -15,74 +15,18 @@
  * 4. Expected: Order confirmation
  */
 
-import type { Env, ServerSession, ServerSessionStatus, BandwidthInfo, RecommendResponse } from '../types';
+import type { Env, ServerSession, ServerSessionStatus, BandwidthInfo, RecommendResponse, OpenAIToolCall, OpenAIMessage, OpenAIAPIResponse } from '../types';
 import { createLogger } from '../utils/logger';
 import { executeSearchWeb, executeLookupDocs } from '../tools/search-tool';
 import { formatTrafficInfo } from '../utils/formatters';
 import { SERVER_CONSULTATION_STATUS, LANGUAGE_CODE } from '../constants';
+import { ServerSessionManager } from '../utils/session-manager';
+import { getSessionConfig } from '../constants/agent-config';
 
 const logger = createLogger('server-agent');
 
-// D1 Session Management
-const SERVER_SESSION_TTL_MS = 60 * 60 * 1000; // 1시간
-
-/**
- * 새 서버 세션 생성
- *
- * @param userId - Telegram User ID
- * @param status - 세션 상태
- * @returns 새로운 ServerSession 객체
- */
-export function createServerSession(
-  userId: string,
-  status: ServerSessionStatus = 'gathering'
-): ServerSession {
-  const now = Date.now();
-  return {
-    user_id: userId,
-    status,
-    collected_info: {},
-    messages: [],
-    created_at: now,
-    updated_at: now,
-    expires_at: now + SERVER_SESSION_TTL_MS,
-  };
-}
-
-/**
- * 세션 만료 여부 확인
- *
- * @param session - ServerSession
- * @returns true if expired, false otherwise
- */
-export function isSessionExpired(session: ServerSession): boolean {
-  return session.expires_at < Date.now();
-}
-
-/**
- * 세션에 메시지 추가
- *
- * @param session - ServerSession
- * @param role - 메시지 역할 ('user' | 'assistant')
- * @param content - 메시지 내용
- */
-export function addMessageToSession(
-  session: ServerSession,
-  role: 'user' | 'assistant',
-  content: string
-): void {
-  session.messages.push({ role, content });
-
-  // 최대 메시지 수 제한 (20개)
-  const MAX_MESSAGES = 20;
-  if (session.messages.length > MAX_MESSAGES) {
-    session.messages = session.messages.slice(-MAX_MESSAGES);
-    logger.warn('세션 메시지 최대 개수 초과, 오래된 메시지 제거', {
-      userId: session.user_id,
-      maxMessages: MAX_MESSAGES,
-    });
-  }
-}
+// Session manager instance
+const sessionManager = new ServerSessionManager(getSessionConfig('server'));
 
 /**
  * 서버 세션 존재 여부 확인 (라우팅용)
@@ -92,122 +36,7 @@ export function addMessageToSession(
  * @returns true if active session exists, false otherwise
  */
 export async function hasServerSession(db: D1Database, userId: string): Promise<boolean> {
-  const session = await getServerSession(db, userId);
-  return session !== null && !isSessionExpired(session);
-}
-
-/**
- * D1에서 서버 세션 조회
- *
- * @param db - D1 Database
- * @param userId - Telegram User ID
- * @returns ServerSession 또는 null (세션 없거나 만료)
- */
-export async function getServerSession(
-  db: D1Database,
-  userId: string
-): Promise<ServerSession | null> {
-  try {
-    const now = Date.now();
-    const result = await db.prepare(
-      'SELECT * FROM server_sessions WHERE user_id = ? AND expires_at > ?'
-    ).bind(userId, now).first<{
-      user_id: string;
-      status: string;
-      collected_info: string | null;
-      last_recommendation: string | null;
-      messages: string | null;
-      created_at: number;
-      updated_at: number;
-      expires_at: number;
-    }>();
-
-    if (!result) {
-      logger.info('세션 없음', { userId });
-      return null;
-    }
-
-    const session: ServerSession = {
-      user_id: result.user_id,
-      status: result.status as ServerSessionStatus,
-      collected_info: result.collected_info ? JSON.parse(result.collected_info) : {},
-      last_recommendation: result.last_recommendation ? JSON.parse(result.last_recommendation) : undefined,
-      messages: result.messages ? JSON.parse(result.messages) : [],
-      created_at: result.created_at,
-      updated_at: result.updated_at,
-      expires_at: result.expires_at,
-    };
-
-    logger.info('세션 조회 성공', { userId, status: session.status, hasLastRecommendation: !!session.last_recommendation });
-    return session;
-  } catch (error) {
-    logger.error('세션 조회 실패', error as Error, { userId });
-    return null;
-  }
-}
-
-/**
- * 서버 세션 저장 (생성 또는 업데이트)
- *
- * @param db - D1 Database
- * @param session - ServerSession
- */
-export async function saveServerSession(
-  db: D1Database,
-  session: ServerSession
-): Promise<void> {
-  try {
-    const now = Date.now();
-    const expiresAt = now + SERVER_SESSION_TTL_MS;
-
-    await db.prepare(`
-      INSERT INTO server_sessions
-        (user_id, status, collected_info, last_recommendation, messages, created_at, updated_at, expires_at)
-      VALUES (?, ?, ?, ?, ?, ?, ?, ?)
-      ON CONFLICT(user_id) DO UPDATE SET
-        status = excluded.status,
-        collected_info = excluded.collected_info,
-        last_recommendation = excluded.last_recommendation,
-        messages = excluded.messages,
-        updated_at = excluded.updated_at,
-        expires_at = excluded.expires_at
-    `).bind(
-      session.user_id,
-      session.status,
-      JSON.stringify(session.collected_info || {}),
-      session.last_recommendation ? JSON.stringify(session.last_recommendation) : null,
-      JSON.stringify(session.messages || []),
-      session.created_at || now,
-      now,
-      expiresAt
-    ).run();
-
-    logger.info('세션 저장 성공', { userId: session.user_id, status: session.status });
-  } catch (error) {
-    logger.error('세션 저장 실패', error as Error, { userId: session.user_id });
-    throw error;
-  }
-}
-
-/**
- * 서버 세션 삭제
- *
- * @param db - D1 Database
- * @param userId - Telegram User ID
- */
-export async function deleteServerSession(
-  db: D1Database,
-  userId: string
-): Promise<void> {
-  try {
-    await db.prepare('DELETE FROM server_sessions WHERE user_id = ?')
-      .bind(userId)
-      .run();
-    logger.info('세션 삭제 성공', { userId });
-  } catch (error) {
-    logger.error('세션 삭제 실패', error as Error, { userId });
-    throw error;
-  }
+  return await sessionManager.has(db, userId);
 }
 
 /**
@@ -516,28 +345,6 @@ function inferExpectedUsers(scale: string, techStack?: string[]): number {
   return 10; // Default to personal
 }
 
-// OpenAI API 응답 타입
-interface OpenAIToolCall {
-  id: string;
-  type: 'function';
-  function: {
-    name: string;
-    arguments: string;
-  };
-}
-
-interface OpenAIMessage {
-  role: 'assistant';
-  content: string | null;
-  tool_calls?: OpenAIToolCall[];
-}
-
-interface OpenAIAPIResponse {
-  choices: Array<{
-    message: OpenAIMessage;
-    finish_reason: string;
-  }>;
-}
 
 /**
  * Server Expert AI 호출 (Function Calling 지원)
@@ -778,11 +585,11 @@ export async function processServerConsultation(
 
   try {
     // 1. Check for existing session
-    let session = await getServerSession(db, userId);
+    let session = await sessionManager.get(db, userId);
 
     // 2. Create new session if none exists
     if (!session) {
-      session = createServerSession(userId, 'gathering');
+      session = sessionManager.create(userId, 'gathering');
     }
 
     // ordering 상태에서 "신청" 외 메시지 입력 시 세션 정리
@@ -790,7 +597,7 @@ export async function processServerConsultation(
       // "신청"은 message-handler에서 처리, 여기까지 오면 다른 메시지임
       const orderConfirmKey = `server_order_confirm:${session.user_id}`;
       await env.SESSION_KV?.delete(orderConfirmKey);
-      await deleteServerSession(db, session.user_id);
+      await sessionManager.delete(db, session.user_id);
 
       logger.info('주문 확인 세션 취소 (다른 메시지 입력)', { userId: session.user_id });
       return '__PASSTHROUGH__';  // 일반 대화로 전환
@@ -800,7 +607,7 @@ export async function processServerConsultation(
     // "취소", "다시", "처음", "리셋", "초기화" 등
     if (/^(취소|다시|처음|리셋|초기화)/.test(userMessage.trim()) ||
         /취소할[게래]|다시\s*시작|처음부터/.test(userMessage)) {
-      await deleteServerSession(db, session.user_id);
+      await sessionManager.delete(db, session.user_id);
       logger.info('사용자 요청으로 상담 취소', {
         userId: session.user_id,
         previousStatus: session.status,
@@ -811,14 +618,14 @@ export async function processServerConsultation(
 
     // "서버 추천" 키워드로 새로 시작 요청 (기존 세션 리셋)
     if (/서버\s*추천/.test(userMessage)) {
-      await deleteServerSession(db, session.user_id);
+      await sessionManager.delete(db, session.user_id);
       logger.info('서버 추천 키워드로 세션 리셋', {
         userId: session.user_id,
         previousStatus: session.status
       });
       // 새 세션 생성하고 시작 메시지 반환
-      const newSession = createServerSession(session.user_id, 'gathering');
-      await saveServerSession(db, newSession);
+      const newSession = sessionManager.create(session.user_id, 'gathering');
+      await sessionManager.save(db, newSession);
       return '안녕하세요! 서버 추천을 도와드리겠습니다. 😊\n\n어떤 서비스를 운영하실 건가요?\n\n1. 웹 서비스 (SaaS, 랜딩페이지)\n2. 모바일 앱 백엔드\n3. AI/ML 서비스 (챗봇, 모델 서빙)\n4. 게임 서버\n5. Discord/Telegram 봇\n6. 자동화 서버 (n8n, 크롤링)\n7. 미디어 스트리밍\n8. 개발/테스트 환경\n9. 데이터베이스 서버\n10. 기타 (직접 입력)\n\n번호나 용도를 말씀해주세요!';
     }
 
@@ -836,7 +643,7 @@ export async function processServerConsultation(
       // 명확히 다른 기능 요청인 경우 세션 종료하고 일반 처리로 전환
       const unrelatedPatterns = /기억|날씨|계산|검색|도메인|입금|충전|잔액|시간|문서/;
       if (unrelatedPatterns.test(userMessage)) {
-        await deleteServerSession(db, session.user_id);
+        await sessionManager.delete(db, session.user_id);
         logger.info('무관한 요청으로 세션 자동 종료', {
           userId: session.user_id,
           message: userMessage.slice(0, 30)
@@ -867,7 +674,7 @@ export async function processServerConsultation(
 
           // Mark session as ordering
           session.status = 'ordering';
-          await saveServerSession(db, session);
+          await sessionManager.save(db, session);
 
           // 주문 확인 세션 저장 (텍스트 기반 확인)
           const orderConfirmKey = `server_order_confirm:${session.user_id}`;
@@ -942,7 +749,7 @@ export async function processServerConsultation(
 
       // Mark session as recommending
       session.status = SERVER_CONSULTATION_STATUS.RECOMMENDING;
-      await saveServerSession(db, session);
+      await sessionManager.save(db, session);
 
       // 1. Call recommendation API (추천 먼저 받기)
       logger.info('추천 API 호출', { collectedInfo: session.collected_info });
@@ -1064,7 +871,7 @@ export async function processServerConsultation(
 
         // Mark session as selecting (사용자 선택 대기)
         session.status = SERVER_CONSULTATION_STATUS.SELECTING;
-        await saveServerSession(db, session);
+        await sessionManager.save(db, session);
 
         // 4. 추천 결과 + AI 검토 코멘트 (검토 코멘트는 마지막에)
         // __DIRECT__ 마커가 앞에 와야 제대로 처리됨
@@ -1072,14 +879,14 @@ export async function processServerConsultation(
       } else {
         // 추천 결과 없음 - 세션 삭제
         session.status = SERVER_CONSULTATION_STATUS.COMPLETED;
-        await deleteServerSession(db, session.user_id);
+        await sessionManager.delete(db, session.user_id);
 
         return `${aiResult.message}\n\n조건에 맞는 서버를 찾지 못했습니다.`;
       }
     } else {
       // Continue gathering information
       session.status = SERVER_CONSULTATION_STATUS.GATHERING;
-      await saveServerSession(db, session);
+      await sessionManager.save(db, session);
 
       return aiResult.message;
     }
@@ -1088,7 +895,7 @@ export async function processServerConsultation(
 
     // Clean up session on error (if exists)
     try {
-      await deleteServerSession(db, userId);
+      await sessionManager.delete(db, userId);
     } catch (deleteError) {
       logger.error('세션 삭제 실패 (무시)', deleteError as Error, { userId });
     }