feat: 优化配置和文件上传

- 上传文件名添加唯一ID避免覆盖
- 支持通过环境变量配置 JWT 密钥和 Token 过期时间
- 支持通过环境变量覆盖管理员账号（可选）

server/config/config.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
 
 	"gopkg.in/yaml.v3"
 )
@@ -260,6 +261,50 @@ func Load() {
 	if cleanedColl := os.Getenv("MONGO_CLEANED_COLLECTION"); cleanedColl != "" {
 		Global.MongoCleanedCollection = cleanedColl
 	}
+	// 认证相关环境变量覆盖
+	if jwtSecret := os.Getenv("JWT_SECRET"); jwtSecret != "" {
+		Global.JWTSecret = jwtSecret
+	}
+	if tokenExpiry := os.Getenv("TOKEN_EXPIRY"); tokenExpiry != "" {
+		if expiry, err := strconv.Atoi(tokenExpiry); err == nil && expiry > 0 {
+			Global.TokenExpiry = expiry
+		}
+	}
+	// 管理员账号环境变量覆盖（覆盖配置文件中的第一个用户）
+	adminUser := os.Getenv("ADMIN_USERNAME")
+	adminPass := os.Getenv("ADMIN_PASSWORD")
+	if adminUser != "" && adminPass != "" {
+		adminName := os.Getenv("ADMIN_NAME")
+		if adminName == "" {
+			adminName = "管理员"
+		}
+		adminEmail := os.Getenv("ADMIN_EMAIL")
+		if adminEmail == "" {
+			adminEmail = adminUser + "@billai.com"
+		}
+		// 查找并更新 admin 用户，或添加新用户
+		found := false
+		for i := range Global.Users {
+			if Global.Users[i].Username == adminUser || Global.Users[i].Role == "admin" {
+				Global.Users[i].Username = adminUser
+				Global.Users[i].Password = adminPass
+				Global.Users[i].Name = adminName
+				Global.Users[i].Email = adminEmail
+				Global.Users[i].Role = "admin"
+				found = true
+				break
+			}
+		}
+		if !found {
+			Global.Users = append(Global.Users, UserInfo{
+				Username: adminUser,
+				Password: adminPass,
+				Name:     adminName,
+				Email:    adminEmail,
+				Role:     "admin",
+			})
+		}
+	}
 }
 
 // ResolvePath 解析路径（相对路径转为绝对路径）