数据层可插拔(SQLite/MariaDB) + 后端 services 骨架

- database.ts 改为按 DB_TYPE 切换 SQLite / MariaDB(mysql2)，sqlite3 按需动态导入
- index.ts 改为初始化数据库后再监听端口
- 新增 AuthService / HealthService / AnalysisService / GarminService
- 新增 .gitignore、server/.env(忽略) 与 .env.example
- README 增加数据库配置说明；package.json 增加 mysql2/@types

server/.env.example

@@ -1,20 +1,21 @@
-# Server Configuration
+# App
 PORT=5000
 NODE_ENV=development
-
-# Database
-DATABASE_PATH=./data/health.db
-
-# JWT
-JWT_SECRET=your_jwt_secret_key_here_change_in_production
-
-# CORS
+JWT_SECRET=generate_a_random_string
 CORS_ORIGIN=http://localhost:3000
 
-# Garmin Configuration
-# Note: Consider using OAuth instead of storing credentials
-GARMIN_CONNECT_USER=your_garmin_email@example.com
-GARMIN_CONNECT_PASSWORD=your_password_here
+# --- Database ---
+# Local/dev: SQLite (zero config)
+# DB_TYPE=sqlite
+# DATABASE_PATH=./data/health.db
+#
+# Production: MariaDB on the NAS
+DB_TYPE=mariadb
+MARIADB_SOCKET=/run/mysqld/mysqld10.sock
+MARIADB_USER=root
+MARIADB_PASSWORD=your_nas_mariadb_root_password
+MARIADB_DATABASE=garmin_health_lab
 
-# Data Sync
-SYNC_INTERVAL_HOURS=1
+# Garmin Connect
+GARMIN_CONNECT_USER=your_garmin_email
+GARMIN_CONNECT_PASSWORD=your_garmin_password