refactor: shared 모듈 추출 Phase 1~4 (notifyHelper, errors, logger, auth, dbPool)

Phase 1: notifyHelper.js → shared/utils/ (4개 서비스 중복 제거)
Phase 2: auth.js → shared/middleware/ (system1/system2 통합)
Phase 3: errors.js + logger.js → shared/utils/ (system1/system2 통합)
Phase 4: DB pool → shared/config/database.js (Group B 4개 서비스 통합)

- Docker 빌드 컨텍스트를 루트로 변경 (6개 API 서비스)
- 기존 파일은 re-export 패턴으로 consumer 변경 0개 유지
- .dockerignore 추가로 빌드 최적화

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tksupport/api/Dockerfile

@@ -1,11 +1,20 @@
 FROM node:18-alpine
 WORKDIR /usr/src/app
-COPY package*.json ./
+
+# shared 모듈 복사
+COPY shared/ ./shared/
+
+COPY tksupport/api/package*.json ./
 RUN npm install --omit=dev
-COPY . .
+
+COPY tksupport/api/ ./
+
 RUN chown -R node:node /usr/src/app
 USER node
+
 EXPOSE 3000
+
 HEALTHCHECK --interval=30s --timeout=3s --start-period=20s --retries=3 \
   CMD node -e "require('http').get('http://localhost:3000/health', (res) => { process.exit(res.statusCode === 200 ? 0 : 1); })"
+
 CMD ["node", "index.js"]

tksupport/api/middleware/auth.js

@@ -1,25 +1,8 @@
 const jwt = require('jsonwebtoken');
-const mysql = require('mysql2/promise');
+const { getPool } = require('../shared/config/database');
 
 const JWT_SECRET = process.env.SSO_JWT_SECRET;
 
-let pool;
-function getPool() {
-  if (!pool) {
-    pool = mysql.createPool({
-      host: process.env.DB_HOST || 'mariadb',
-      port: parseInt(process.env.DB_PORT) || 3306,
-      user: process.env.DB_USER || 'hyungi_user',
-      password: process.env.DB_PASSWORD,
-      database: process.env.DB_NAME || 'hyungi',
-      waitForConnections: true,
-      connectionLimit: 5,
-      queueLimit: 0
-    });
-  }
-  return pool;
-}
-
 function extractToken(req) {
   const authHeader = req.headers['authorization'];
   if (authHeader && authHeader.startsWith('Bearer ')) {