feat: migrate from SQLite to PostgreSQL + Redis architecture

Major database migration to modernize the AI trading system:

• **Database Migration**:
  - Add PostgreSQL 15 and Redis 7 services to docker-compose
  - Create comprehensive PostgreSQL schema with proper indexes and triggers
  - Implement DatabaseInterface for multi-database support
  - Add automatic environment-based database selection

• **Infrastructure**:
  - PostgreSQL: ACID transactions, better concurrency, JSON support
  - Redis: High-performance caching layer (prepared for future use)
  - Docker services with health checks and dependency management
  - Persistent volumes for data safety

• **Code Refactoring**:
  - Abstract database operations through DatabaseInterface
  - Implement PostgreSQL-specific operations with proper syntax
  - Update all SQL queries to support both SQLite and PostgreSQL
  - Fix foreign key constraints and data type conversions

• **Migration Tools**:
  - Automated data migration script from SQLite to PostgreSQL
  - Complete backup and restore procedures
  - One-click migration script with validation

• **Compatibility**:
  - Backward compatible with existing SQLite deployments
  - Environment variable driven database selection
  - Preserved all existing functionality and data

🎯 Benefits: Better performance, scalability, and reliability for production deployments

main.go

@@ -41,7 +41,7 @@ type ConfigFile struct {
 }
 
 // syncConfigToDatabase 从config.json读取配置并同步到数据库
-func syncConfigToDatabase(database *config.Database) error {
+func syncConfigToDatabase(database config.DatabaseInterface) error {
 	// 检查config.json是否存在
 	if _, err := os.Stat("config.json"); os.IsNotExist(err) {
 		log.Printf("📄 config.json不存在，跳过同步")
@@ -110,7 +110,7 @@ func syncConfigToDatabase(database *config.Database) error {
 }
 
 // loadBetaCodesToDatabase 加载内测码文件到数据库
-func loadBetaCodesToDatabase(database *config.Database) error {
+func loadBetaCodesToDatabase(database config.DatabaseInterface) error {
 	betaCodeFile := "beta_codes.txt"
 	
 	// 检查内测码文件是否存在