支持动态更新管理员密码和下载次数逻辑完善，优化相关错误处理和配置更新流程

internal/api/admin/config.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 
 	"github.com/gin-gonic/gin"
+	"golang.org/x/crypto/bcrypt"
 )
 
 type ConfigHandler struct{}
@@ -52,6 +53,16 @@ func (h *ConfigHandler) UpdateConfig(c *gin.Context) {
 		newConfig.Database.Path = config.GlobalConfig.Database.Path
 	}
 
+	// 如果传入了明文密码，则重新生成 hash
+	if newConfig.Security.AdminPassword != "" {
+		hash, err := bcrypt.GenerateFromPassword([]byte(newConfig.Security.AdminPassword), bcrypt.DefaultCost)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, model.ErrorResponse(model.CodeInternalError, "Failed to hash password: "+err.Error()))
+			return
+		}
+		newConfig.Security.AdminPasswordHash = string(hash)
+	}
+
 	// 检查取件码长度是否变化
 	pickupCodeLengthChanged := newConfig.Security.PickupCodeLength != config.GlobalConfig.Security.PickupCodeLength && newConfig.Security.PickupCodeLength > 0