feat: migrate store layer to GORM with PostgreSQL support

- Migrate all store packages from raw database/sql to GORM ORM
- Add PostgreSQL support alongside SQLite
- Move EncryptedString type to crypto package for cleaner architecture
- Add automatic encryption/decryption for sensitive fields (API keys, secrets)
- Fix PostgreSQL AutoMigrate conflicts by skipping existing tables
- Fix duplicate /klines route registration
- Update tests to use GORM database connections
- Add database configuration support in config package

.env.example

@@ -55,3 +55,16 @@ TRANSPORT_ENCRYPTION=false
 # Telegram notifications (optional)
 # TELEGRAM_BOT_TOKEN=your-bot-token
 # TELEGRAM_CHAT_ID=your-chat-id
+
+DB_TYPE=postgres
+DB_HOST=10.
+DB_PORT=5432
+DB_USER=nofx_user
+DB_PASSWORD=
+DB_NAME=nofx
+DB_SSLMODE=disable
+
+
+# 数据库配置 - SQLite（默认）
+DB_TYPE=sqlite
+DB_PATH=data/data.db