feat: implement hybrid database architecture and frontend encryption

- Add PostgreSQL + SQLite hybrid database support with automatic switching
- Implement frontend AES-GCM + RSA-OAEP encryption for sensitive data
- Add comprehensive DatabaseInterface with all required methods
- Fix compilation issues with interface consistency
- Update all database method signatures to use DatabaseInterface
- Add missing UpdateTraderInitialBalance method to PostgreSQL implementation
- Integrate RSA public key distribution via /api/config endpoint
- Add frontend crypto service with proper error handling
- Support graceful degradation between encrypted and plaintext transmission
- Add directory creation for RSA keys and PEM parsing fixes
- Test both SQLite and PostgreSQL modes successfully

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: tinkle-community <tinklefund@gmail.com>

start.sh

@@ -165,6 +165,16 @@ start() {
     # 读取环境变量
     read_env_vars
 
+    # 确保必要的文件和目录存在（修复 Docker volume 挂载问题）
+    if [ ! -f "config.db" ]; then
+        print_info "创建数据库文件..."
+        touch config.db
+    fi
+    if [ ! -d "decision_logs" ]; then
+        print_info "创建日志目录..."
+        mkdir -p decision_logs
+    fi
+
     # Auto-build frontend if missing or forced
     # if [ ! -d "web/dist" ] || [ "$1" == "--build" ]; then
     #     build_frontend