feat: 更新 Server 后端服务

- 更新 agent handler 和 service 层
- 新增 chat_group handler 和 service
- 删除废弃的 chat_handler
- 更新 tool 相关处理
- 更新 API 文档和依赖

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/internal/config/config.go

@@ -3,7 +3,10 @@ package config
 import (
 	"fmt"
 	"log"
+	"os"
+	"path/filepath"
 
+	"github.com/glebarez/sqlite"
 	"gorm.io/driver/mysql"
 	"gorm.io/gorm"
 	"gorm.io/gorm/logger"
@@ -11,15 +14,31 @@ import (
 	"github.com/spf13/viper"
 )
 
+// 获取项目根目录
+func getProjectRoot() string {
+	// 从当前工作目录向上查找 .env 文件
+	dir, _ := os.Getwd()
+	for i := 0; i < 5; i++ {
+		if _, err := os.Stat(filepath.Join(dir, ".env")); err == nil {
+			return dir
+		}
+		dir = filepath.Dir(dir)
+	}
+	// 默认返回当前目录
+	return "."
+}
+
 type Config struct {
 	Port              string
 	JWTSecret         string
+	DatabaseType      string // 数据库类型: mysql 或 sqlite
 	DatabaseHost      string
 	DatabasePort      string
 	DatabaseUser      string
 	DatabasePassword  string
 	DatabaseName      string
 	DatabaseURL       string // 拼接后的完整连接字符串
+	SQLitePath        string // SQLite 数据库文件路径
 	PythonServiceURL  string
 	AICoreServiceAddr string // AI-Core gRPC 服务地址，如 "localhost:50051"
 	// 文件上传配置
@@ -36,23 +55,22 @@ type Config struct {
 }
 
 func Load() *Config {
-	viper.SetConfigName("config")
-	viper.SetConfigType("yaml")
-	viper.AddConfigPath("./config")
-	viper.AddConfigPath("../config")
-	viper.AddConfigPath("../../config")
+	// 重新初始化 viper，避免之前的状态影响
+	viper.Reset()
 
-	// 默认值
+	// 第一步：设置默认值
 	viper.SetDefault("port", "8080")
 	viper.SetDefault("jwt_secret", "your-secret-key-change-in-production")
 	viper.SetDefault("python_service_url", "http://localhost:8081")
 	viper.SetDefault("ai_core_service_addr", "localhost:50051")
 	// 数据库默认配置
+	viper.SetDefault("database_type", "mysql")
 	viper.SetDefault("database_host", "localhost")
 	viper.SetDefault("database_port", "3306")
 	viper.SetDefault("database_user", "root")
 	viper.SetDefault("database_password", "root")
 	viper.SetDefault("database_name", "x_agents")
+	viper.SetDefault("sqlite_path", "./data/x_agents.db")
 	// 文件上传默认配置
 	viper.SetDefault("upload_mode", "local")
 	viper.SetDefault("upload_local_path", "resource/files")
@@ -64,30 +82,84 @@ func Load() *Config {
 	viper.SetDefault("minio_bucket", "x-agents")
 	viper.SetDefault("minio_use_ssl", false)
 
-	if err := viper.ReadInConfig(); err != nil {
-		log.Printf("Using default config: %v", err)
+	// 第二步：读取 config.yaml（优先级低）
+	viper.SetConfigName("config")
+	viper.SetConfigType("yaml")
+	viper.AddConfigPath("./config")
+	viper.AddConfigPath("../config")
+	viper.AddConfigPath("../../config")
+	_ = viper.MergeInConfig() // 忽略错误，可能没有 config.yaml
+
+	// 第三步：读取 .env 文件（优先级最高）
+	projectRoot := getProjectRoot()
+	log.Printf("Project root: %s", projectRoot)
+
+	viper.SetConfigName(".env")
+	viper.SetConfigType("env")
+	viper.AddConfigPath(projectRoot)  // 项目根目录 (X-Agents)
+	viper.AddConfigPath(".")          // 当前目录
+	viper.AddConfigPath("..")         // 父目录
+	viper.AddConfigPath("../..")      // 上两级目录
+	viper.SetEnvPrefix("GO")          // 环境变量前缀 GO_xxx (仅对环境变量生效)
+	viper.AutomaticEnv()
+	_ = viper.MergeInConfig() // 忽略错误，可能没有 .env
+
+	// 处理 .env 文件中的键名（去掉 GO_ 前缀映射）
+	envToConfig := map[string]string{
+		"GO_PORT":              "port",
+		"GO_DATABASE_TYPE":     "database_type",
+		"GO_DATABASE_HOST":     "database_host",
+		"GO_DATABASE_PORT":     "database_port",
+		"GO_DATABASE_NAME":     "database_name",
+		"GO_DATABASE_USER":     "database_user",
+		"GO_DATABASE_PASSWORD": "database_password",
+		"GO_SQLITE_PATH":      "sqlite_path",
+	}
+	for envKey, configKey := range envToConfig {
+		if val := viper.GetString(envKey); val != "" {
+			viper.Set(configKey, val)
+		}
 	}
 
-	// 拼接数据库连接字符串
-	dbHost := viper.GetString("database_host")
-	dbPort := viper.GetString("database_port")
-	dbUser := viper.GetString("database_user")
-	dbPassword := viper.GetString("database_password")
-	dbName := viper.GetString("database_name")
-	databaseURL := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local",
-		dbUser, dbPassword, dbHost, dbPort, dbName)
+	log.Printf("Loaded config: database_type=%s, port=%s",
+		viper.GetString("database_type"), viper.GetString("port"))
+
+	// 获取数据库类型
+	dbType := viper.GetString("database_type")
+	var databaseURL string
+
+	if dbType == "sqlite" {
+		sqlitePath := viper.GetString("sqlite_path")
+		// 确保 SQLite 数据目录存在 (跨平台处理)
+		dir := filepath.Dir(sqlitePath)
+		if dir != "." && dir != "" {
+			os.MkdirAll(dir, 0755)
+		}
+		databaseURL = sqlitePath
+	} else {
+		// MySQL 连接字符串
+		dbHost := viper.GetString("database_host")
+		dbPort := viper.GetString("database_port")
+		dbUser := viper.GetString("database_user")
+		dbPassword := viper.GetString("database_password")
+		dbName := viper.GetString("database_name")
+		databaseURL = fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local",
+			dbUser, dbPassword, dbHost, dbPort, dbName)
+	}
 
 	return &Config{
 		Port:              viper.GetString("port"),
 		JWTSecret:         viper.GetString("jwt_secret"),
+		DatabaseType:      dbType,
 		DatabaseURL:       databaseURL,
-		DatabaseHost:      dbHost,
-		DatabasePort:      dbPort,
-		DatabaseUser:      dbUser,
-		DatabasePassword:  dbPassword,
-		DatabaseName:      dbName,
+		DatabaseHost:      viper.GetString("database_host"),
+		DatabasePort:      viper.GetString("database_port"),
+		DatabaseUser:      viper.GetString("database_user"),
+		DatabasePassword:  viper.GetString("database_password"),
+		DatabaseName:      viper.GetString("database_name"),
+		SQLitePath:        viper.GetString("sqlite_path"),
 		PythonServiceURL:  viper.GetString("python_service_url"),
-		AICoreServiceAddr:  viper.GetString("ai_core_service_addr"),
+		AICoreServiceAddr: viper.GetString("ai_core_service_addr"),
 		// 文件上传配置
 		UploadMode:        viper.GetString("upload_mode"),
 		UploadLocalPath:   viper.GetString("upload_local_path"),
@@ -108,9 +180,23 @@ func InitDB(cfg *Config) (*gorm.DB, error) {
 		return nil, fmt.Errorf("database URL is empty")
 	}
 
-	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
-		Logger: logger.Default.LogMode(logger.Silent),
-	})
+	var db *gorm.DB
+	var err error
+
+	if cfg.DatabaseType == "sqlite" {
+		// SQLite 不需要创建目录逻辑，因为 Load 函数已经处理了
+		db, err = gorm.Open(sqlite.Open(dsn), &gorm.Config{
+			Logger: logger.Default.LogMode(logger.Silent),
+		})
+		log.Printf("Using SQLite database: %s", dsn)
+	} else {
+		db, err = gorm.Open(mysql.Open(dsn), &gorm.Config{
+			Logger: logger.Default.LogMode(logger.Silent),
+		})
+		log.Printf("Using MySQL database: %s:%s/%s",
+			cfg.DatabaseHost, cfg.DatabasePort, cfg.DatabaseName)
+	}
+
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect database: %w", err)
 	}