fix: self-heal застрявших pending changes при broken project reference

- ensureConfigurationProject: если project не найден ни на сервере, ни локально
  (stale UUID после удаления), падаем в fallback «Без проекта» вместо вечной ошибки
- PushPendingChanges: автоматически вызывает RepairPendingChanges() перед циклом,
  чтобы локально-исправимые проблемы чинились до попытки отправки
- maxPendingChangeAttempts=20: после 20 неудачных попыток change считается
  unrecoverable и удаляется из очереди (логируется ERROR)
- pushSingleChange/pushConfigurationChange: unknown entity type / operation
  теперь дропается с warn вместо вечного error в цикле
- latestSyncErrorState: last_sync_error_text в qt_client_schema_state теперь
  содержит JSON-массив с type/uuid/op/attempts/error по всем застрявшим changes
  (до 20 штук) вместо текста только последней ошибки

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/services/sync/readiness.go

@@ -1,6 +1,7 @@
 package sync
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -320,14 +321,37 @@ func latestSyncErrorState(local *localdb.LocalDB) (*string, *string) {
 		return optionalString(strings.TrimSpace(guard.ReasonCode)), optionalString(strings.TrimSpace(guard.ReasonText))
 	}
 
-	var pending localdb.PendingChange
+	var errored []localdb.PendingChange
 	if err := local.DB().
 		Where("TRIM(COALESCE(last_error, '')) <> ''").
 		Order("id DESC").
-		First(&pending).Error; err == nil {
+		Limit(20).
-		return optionalString("PENDING_CHANGE_ERROR"), optionalString(strings.TrimSpace(pending.LastError))
+		Find(&errored).Error; err != nil || len(errored) == 0 {
+		return nil, nil
 	}
-	return nil, nil
+
+	type errorEntry struct {
+		Type     string `json:"type"`
+		UUID     string `json:"uuid"`
+		Op       string `json:"op"`
+		Attempts int    `json:"attempts"`
+		Error    string `json:"error"`
+	}
+	entries := make([]errorEntry, 0, len(errored))
+	for _, ch := range errored {
+		entries = append(entries, errorEntry{
+			Type:     ch.EntityType,
+			UUID:     ch.EntityUUID,
+			Op:       ch.Operation,
+			Attempts: ch.Attempts,
+			Error:    strings.TrimSpace(ch.LastError),
+		})
+	}
+	detail, jsonErr := json.Marshal(entries)
+	if jsonErr != nil {
+		return optionalString("PENDING_CHANGE_ERROR"), optionalString(strings.TrimSpace(errored[0].LastError))
+	}
+	return optionalString("PENDING_CHANGE_ERROR"), optionalString(string(detail))
 }
 
 func optionalString(value string) *string {

internal/services/sync/service.go

@@ -851,6 +851,11 @@ func (s *Service) SyncPricelistsIfNeeded() error {
 	return nil
 }
 
+// maxPendingChangeAttempts is the number of failed attempts after which a pending change
+// is considered unrecoverable and removed from the queue. Applies only to changes that
+// fail with a non-transient error (e.g. corrupt payload, unknown operation).
+const maxPendingChangeAttempts = 20
+
 // PushPendingChanges pushes all pending changes to the server
 func (s *Service) PushPendingChanges() (int, error) {
 	if _, err := s.EnsureReadinessForSync(); err != nil {
@@ -864,6 +869,14 @@ func (s *Service) PushPendingChanges() (int, error) {
 		slog.Info("purged orphan configuration pending changes", "removed", removed)
 	}
 
+	// Auto-repair locally-fixable problems (e.g. stale project references)
+	// before attempting to push, so that repaired changes succeed on this cycle.
+	if repaired, _, repairErr := s.localDB.RepairPendingChanges(); repairErr != nil {
+		slog.Warn("auto-repair of errored pending changes failed", "error", repairErr)
+	} else if repaired > 0 {
+		slog.Info("auto-repaired errored pending changes", "repaired", repaired)
+	}
+
 	changes, err := s.localDB.GetPendingChanges()
 	if err != nil {
 		return 0, fmt.Errorf("getting pending changes: %w", err)
@@ -884,8 +897,14 @@ func (s *Service) PushPendingChanges() (int, error) {
 		if err != nil {
 			s.markConnectionBroken(err)
 			slog.Warn("failed to push change", "id", change.ID, "type", change.EntityType, "operation", change.Operation, "error", err)
-			// Increment attempts
+			newAttempts := change.Attempts + 1
 			s.localDB.IncrementPendingChangeAttempts(change.ID, err.Error())
+			if newAttempts >= maxPendingChangeAttempts {
+				slog.Error("abandoning pending change after max attempts",
+					"id", change.ID, "type", change.EntityType, "op", change.Operation,
+					"attempts", newAttempts, "last_error", err.Error())
+				syncedIDs = append(syncedIDs, change.ID)
+			}
 			continue
 		}
 
@@ -912,7 +931,11 @@ func (s *Service) pushSingleChange(change *localdb.PendingChange) error {
 	case "configuration":
 		return s.pushConfigurationChange(change)
 	default:
-		return fmt.Errorf("unknown entity type: %s", change.EntityType)
+		// Unknown entity type: this change was queued by a newer or different build
+		// and cannot be processed. Remove it from the queue.
+		slog.Warn("dropping pending change with unknown entity type",
+			"id", change.ID, "type", change.EntityType, "op", change.Operation)
+		return nil
 	}
 }
 
@@ -1045,7 +1068,10 @@ func (s *Service) pushConfigurationChange(change *localdb.PendingChange) error {
 	case "delete":
 		return s.pushConfigurationDelete(change)
 	default:
-		return fmt.Errorf("unknown operation: %s", change.Operation)
+		// Unknown operation: queued by a newer or different build. Drop from queue.
+		slog.Warn("dropping pending change with unknown operation",
+			"id", change.ID, "type", change.EntityType, "op", change.Operation)
+		return nil
 	}
 }
 
@@ -1245,24 +1271,30 @@ func (s *Service) ensureConfigurationProject(mariaDB *gorm.DB, cfg *models.Confi
 
 		localProject, localErr := s.localDB.GetProjectByUUID(*cfg.ProjectUUID)
 		if localErr != nil {
-			return err
+			// Project not found locally either: stale reference (project was deleted).
+			// Fall through to system project so this configuration is not stuck forever.
+			slog.Warn("configuration references missing project, assigning to system project",
+				"cfg_uuid", cfg.UUID,
+				"project_uuid", *cfg.ProjectUUID,
+			)
+		} else {
+			modelProject := localdb.LocalToProject(localProject)
+			if modelProject.OwnerUsername == "" {
+				modelProject.OwnerUsername = cfg.OwnerUsername
+			}
+			if createErr := projectRepo.UpsertByUUID(modelProject); createErr != nil {
+				return createErr
+			}
+			if modelProject.ID > 0 {
+				serverID := modelProject.ID
+				localProject.ServerID = &serverID
+				localProject.SyncStatus = "synced"
+				now := time.Now()
+				localProject.SyncedAt = &now
+				_ = s.localDB.SaveProjectPreservingUpdatedAt(localProject)
+			}
+			return nil
 		}
-		modelProject := localdb.LocalToProject(localProject)
-		if modelProject.OwnerUsername == "" {
-			modelProject.OwnerUsername = cfg.OwnerUsername
-		}
-		if createErr := projectRepo.UpsertByUUID(modelProject); createErr != nil {
-			return createErr
-		}
-		if modelProject.ID > 0 {
-			serverID := modelProject.ID
-			localProject.ServerID = &serverID
-			localProject.SyncStatus = "synced"
-			now := time.Now()
-			localProject.SyncedAt = &now
-			_ = s.localDB.SaveProjectPreservingUpdatedAt(localProject)
-		}
-		return nil
 	}
 
 	systemProject := &models.Project{}