fix: remove tenant dependency from member login

internal/auth/auth.go

@@ -46,17 +46,13 @@ func New(cfg config.AuthConfig, redisClient *redis.Client) *Authenticator {
 	return &Authenticator{cfg: cfg, redis: redisClient}
 }
 
-func (a *Authenticator) DefaultTenantID() int64 {
-	return a.cfg.DefaultTenantID
-}
-
 func (a *Authenticator) Authenticate(req *http.Request) (*Principal, error) {
 	if err := a.ValidateAPIKey(req); err != nil {
 		return nil, err
 	}
 	if a.cfg.AllowDevHeaderAuth {
 		if memberID := parseInt64Header(req, "X-Member-ID"); memberID > 0 {
-			return &Principal{TenantID: a.cfg.DefaultTenantID, MemberID: memberID,
+			return &Principal{TenantID: 0, MemberID: memberID,
 				DeviceID: strings.TrimSpace(req.Header.Get("X-Device-ID"))}, nil
 		}
 	}