fix: tolerate missing schema_fingerprints table in BDD cleanup

The schema_fingerprints table may not exist if the schema-registry
hasn't finished migrating when the first BDD scenario cleanup runs.
Handle the "unconfigured table" error gracefully instead of failing
hard, which was causing the BDD Cassandra tests to hang.

Author: millerjp

tests/bdd/bdd_test.go

@@ -330,13 +330,20 @@ func cleanCassandra() error {
 		"id_alloc", "modes", "global_config", "subject_configs",
 		"references_by_target", "schema_references",
 		"subject_latest", "subject_versions",
-		"schemas_by_id", "schema_fingerprints",
+		"schemas_by_id",
 	}
 	for _, t := range tables {
 		if err := session.Query("TRUNCATE " + t).Exec(); err != nil {
 			return fmt.Errorf("truncate %s: %w", t, err)
 		}
 	}
+	// schema_fingerprints may not exist on older schema-registry images;
+	// ignore "unconfigured table" errors so cleanup stays compatible.
+	if err := session.Query("TRUNCATE schema_fingerprints").Exec(); err != nil {
+		if !strings.Contains(err.Error(), "unconfigured table") {
+			return fmt.Errorf("truncate schema_fingerprints: %w", err)
+		}
+	}
 
 	// Re-seed id_alloc so GetMaxSchemaID works (block-based allocator
 	// caches IDs in-process, but GetMaxSchemaID reads from the table).