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

.gitignore

@@ -1,27 +1,29 @@
+# Dependencies
 node_modules/
-dist/
-build/
-*.log
-npm-debug.log*
-.DS_Store
+
+# Env (contains secrets - never commit)
 .env
 .env.local
 .env.*.local
-.idea/
-.vscode/
-*.swp
-*.swo
-~*
 
-# Database
+# Local SQLite data
+data/
 *.db
 *.sqlite
 *.sqlite3
 
-# API Keys and secrets
-.env.production.local
-config/secrets.json
+# Build output
+dist/
+build/
 
-# Build artifacts
-server/dist/
-client/build/
+# Logs
+logs/
+*.log
+
+# OS / editor
+.DS_Store
+.idea/
+.vscode/
+
+# WorkBuddy tool state (not project code)
+.workbuddy/