fix: handle database permission issues in sync migration verification

Sync was blocked because the migration registry table creation required
CREATE TABLE permissions that the database user might not have.

Changes:
- Check if migration registry tables exist before attempting to create them
- Skip creation if table exists and user lacks CREATE permissions
- Use information_schema to reliably check table existence
- Apply same fix to user sync status table creation
- Gracefully handle ALTER TABLE failures for backward compatibility

This allows sync to proceed even if the client is a read-limited database user,
as long as the required tables have already been created by an administrator.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

internal/services/sync/readiness.go

@@ -189,33 +189,54 @@ func listActiveClientMigrations(db *gorm.DB) ([]clientLocalMigration, error) {
 }
 
 func ensureClientMigrationRegistryTable(db *gorm.DB) error {
-	if err := db.Exec(`
-		CREATE TABLE IF NOT EXISTS qt_client_local_migrations (
-			id VARCHAR(128) NOT NULL,
-			name VARCHAR(255) NOT NULL,
-			sql_text LONGTEXT NOT NULL,
-			checksum VARCHAR(128) NOT NULL,
-			min_app_version VARCHAR(64) NULL,
-			order_no INT NOT NULL DEFAULT 0,
-			is_active TINYINT(1) NOT NULL DEFAULT 1,
-			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
-			PRIMARY KEY (id),
-			INDEX idx_qt_client_local_migrations_active_order (is_active, order_no, created_at)
-		)
-	`).Error; err != nil {
-		return err
+	// Check if table exists instead of trying to create (avoids permission issues)
+	if !tableExists(db, "qt_client_local_migrations") {
+		if err := db.Exec(`
+			CREATE TABLE IF NOT EXISTS qt_client_local_migrations (
+				id VARCHAR(128) NOT NULL,
+				name VARCHAR(255) NOT NULL,
+				sql_text LONGTEXT NOT NULL,
+				checksum VARCHAR(128) NOT NULL,
+				min_app_version VARCHAR(64) NULL,
+				order_no INT NOT NULL DEFAULT 0,
+				is_active TINYINT(1) NOT NULL DEFAULT 1,
+				created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+				PRIMARY KEY (id),
+				INDEX idx_qt_client_local_migrations_active_order (is_active, order_no, created_at)
+			)
+		`).Error; err != nil {
+			return fmt.Errorf("create qt_client_local_migrations table: %w", err)
+		}
 	}
-	return db.Exec(`
-		CREATE TABLE IF NOT EXISTS qt_client_schema_state (
-			username VARCHAR(100) NOT NULL,
-			last_applied_migration_id VARCHAR(128) NULL,
-			app_version VARCHAR(64) NULL,
-			last_checked_at DATETIME NOT NULL,
-			updated_at DATETIME NOT NULL,
-			PRIMARY KEY (username),
-			INDEX idx_qt_client_schema_state_checked (last_checked_at)
-		)
-	`).Error
+
+	if !tableExists(db, "qt_client_schema_state") {
+		if err := db.Exec(`
+			CREATE TABLE IF NOT EXISTS qt_client_schema_state (
+				username VARCHAR(100) NOT NULL,
+				last_applied_migration_id VARCHAR(128) NULL,
+				app_version VARCHAR(64) NULL,
+				last_checked_at DATETIME NOT NULL,
+				updated_at DATETIME NOT NULL,
+				PRIMARY KEY (username),
+				INDEX idx_qt_client_schema_state_checked (last_checked_at)
+			)
+		`).Error; err != nil {
+			return fmt.Errorf("create qt_client_schema_state table: %w", err)
+		}
+	}
+	return nil
+}
+
+func tableExists(db *gorm.DB, tableName string) bool {
+	var count int64
+	// For MariaDB/MySQL, check information_schema
+	if err := db.Raw(`
+		SELECT COUNT(*) FROM information_schema.TABLES
+		WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ?
+	`, tableName).Scan(&count).Error; err != nil {
+		return false
+	}
+	return count > 0
 }
 
 func (s *Service) applyMissingRemoteMigrations(migrations []clientLocalMigration) error {

internal/services/sync/service.go

@@ -553,24 +553,34 @@ func (s *Service) listConnectedDBUsers(mariaDB *gorm.DB) (map[string]struct{}, e
 }
 
 func ensureUserSyncStatusTable(db *gorm.DB) error {
-	if err := db.Exec(`
-		CREATE TABLE IF NOT EXISTS qt_pricelist_sync_status (
-			username VARCHAR(100) NOT NULL,
-			last_sync_at DATETIME NOT NULL,
-			updated_at DATETIME NOT NULL,
-			app_version VARCHAR(64) NULL,
-			PRIMARY KEY (username),
-			INDEX idx_qt_pricelist_sync_status_last_sync (last_sync_at)
-		)
-	`).Error; err != nil {
-		return err
+	// Check if table exists instead of trying to create (avoids permission issues)
+	if !tableExists(db, "qt_pricelist_sync_status") {
+		if err := db.Exec(`
+			CREATE TABLE IF NOT EXISTS qt_pricelist_sync_status (
+				username VARCHAR(100) NOT NULL,
+				last_sync_at DATETIME NOT NULL,
+				updated_at DATETIME NOT NULL,
+				app_version VARCHAR(64) NULL,
+				PRIMARY KEY (username),
+				INDEX idx_qt_pricelist_sync_status_last_sync (last_sync_at)
+			)
+		`).Error; err != nil {
+			return fmt.Errorf("create qt_pricelist_sync_status table: %w", err)
+		}
 	}
 
 	// Backward compatibility for environments where table was created without app_version.
-	return db.Exec(`
-		ALTER TABLE qt_pricelist_sync_status
-		ADD COLUMN IF NOT EXISTS app_version VARCHAR(64) NULL
-	`).Error
+	// Only try to add column if table exists.
+	if tableExists(db, "qt_pricelist_sync_status") {
+		if err := db.Exec(`
+			ALTER TABLE qt_pricelist_sync_status
+			ADD COLUMN IF NOT EXISTS app_version VARCHAR(64) NULL
+		`).Error; err != nil {
+			// Log but don't fail if alter fails (column might already exist)
+			slog.Debug("failed to add app_version column", "error", err)
+		}
+	}
+	return nil
 }
 
 // SyncPricelistItems synchronizes items for a specific pricelist