feat(cfg): Add user creation hook

- Add `OnUserCreate` hook variable in `cfg/cfg.go` for custom callbacks
    - Invoke `OnUserCreate` after successful user registration in `api/auth/register.go`
    - Log warning when user creation hook fails

api/auth/register.go

@@ -18,6 +18,7 @@ import (
 	"github.com/veypi/vbase/libs/jwt"
 	"github.com/veypi/vbase/models"
 	"github.com/veypi/vigo"
+	"github.com/veypi/vigo/logv"
 	"gorm.io/gorm"
 )
 
@@ -158,6 +159,9 @@ func register(x *vigo.X, req *RegisterRequest) (*AuthResponse, error) {
 	if err != nil {
 		return nil, err
 	}
+	if err := cfg.OnUserCreate(user.ID); err != nil {
+		logv.Warn().Msgf("user create hook failed: %s", err)
+	}
 
 	// 授予角色（事务外，因为事务已确保用户创建成功）
 	roleCode := "user"

cfg/cfg.go

@@ -78,3 +78,7 @@ var Redis = Global.Redis.Client
 
 // Auth 是全局的权限检查对象，通过 SetProvider 注入 Provider 实现
 var Auth = auth.New()
+
+var OnUserCreate = func(user_id string) error {
+	return nil
+}