fix(sync): mark node dirty inside the mutation transaction (atomic ConfigDirty) (#5611)

* fix(sync): mark node dirty inside the mutation transaction

ConfigDirty is currently set by MarkNodeDirty AFTER the mutation, on a
separate DB handle outside the mutation's transaction. A crash or error
between the committed change and the mark leaves a committed config
change that never reconciles to the node (silent drift). Add
MarkNodeDirtyTx(tx, id) and call it inside each mutation's transaction so
the dirty mark commits atomically with the change.

* fix(test): initialize DB in TestResolveInboundAddress and group gorm import

Two CI failures on this branch:

- race (-shuffle=on): TestResolveInboundAddress reaches resolveInboundAddress -> configuredPublicHost -> GetSubDomain, which reads the global DB. The test never initialized one, relying on another sub-package test to do so first; under shuffle it ran first and nil-dereferenced gorm. Call initSubDB(t) so it is self-sufficient (empty DB yields an empty subDomain, so the subscriber-host fallback still holds).

- golangci goimports: gorm.io/gorm was grouped with the github.com/mhsanaei/3x-ui local imports in node_dirty_test.go. Move it into the third-party group.

internal/web/service/node.go

@@ -453,12 +453,14 @@ func (s *NodeService) Update(id int, in *model.Node) error {
 		"inbound_tags":          string(inboundTagsJSON),
 		"outbound_tag":          in.OutboundTag,
 	}
-	if err := db.Model(model.Node{}).Where("id = ?", id).Updates(updates).Error; err != nil {
+	if err := db.Transaction(func(tx *gorm.DB) error {
+		if err := tx.Model(model.Node{}).Where("id = ?", id).Updates(updates).Error; err != nil {
+			return err
+		}
+		return s.MarkNodeDirtyTx(tx, id)
+	}); err != nil {
 		return err
 	}
-	if dErr := s.MarkNodeDirty(id); dErr != nil {
-		logger.Warning("mark node dirty after update failed:", dErr)
-	}
 	if mgr := runtime.GetManager(); mgr != nil {
 		mgr.InvalidateNode(id)
 	}
@@ -736,10 +738,17 @@ func (s *NodeService) warnOnDuplicateGuid(id int, guid string) {
 }
 
 func (s *NodeService) MarkNodeDirty(id int) error {
+	return s.MarkNodeDirtyTx(database.GetDB(), id)
+}
+
+func (s *NodeService) MarkNodeDirtyTx(tx *gorm.DB, id int) error {
 	if id <= 0 {
 		return nil
 	}
-	return database.GetDB().Model(model.Node{}).
+	if tx == nil {
+		return errors.New("nil db transaction")
+	}
+	return tx.Model(model.Node{}).
 		Where("id = ?", id).
 		Updates(map[string]any{
 			"config_dirty":    true,