test(tools): add unit tests for error handling functions

* Implement tests for error functions like errRequiredField, errInvalidField, and errEntityNotFound.
* Ensure proper metadata is returned for various error scenarios.
* Validate error handling in CRM, Files, and other tools.
* Introduce tests for parsing stored file IDs and UUIDs.
* Enhance coverage for helper functions related to project resolution and session management.

internal/store/files.go

@@ -136,7 +136,9 @@ func (db *DB) AddThoughtAttachment(ctx context.Context, thoughtID uuid.UUID, att
 	if err != nil {
 		return fmt.Errorf("begin transaction: %w", err)
 	}
-	defer tx.Rollback(ctx)
+	defer func() {
+		_ = tx.Rollback(ctx)
+	}()
 
 	var metadataBytes []byte
 	if err := tx.QueryRow(ctx, `select metadata from thoughts where guid = $1 for update`, thoughtID).Scan(&metadataBytes); err != nil {