Honor explicitly selected custom storage backends

tests/test_configuration_regressions.py

@@ -0,0 +1,19 @@
+from great_ai import ParallelTinyDbDriver, configure
+from great_ai.context import get_context
+from great_ai.large_file import LargeFileLocal
+
+
+def test_explicit_custom_backends_are_preserved(isolated_context: None) -> None:
+    class CustomDatabase(ParallelTinyDbDriver):
+        pass
+
+    class CustomStorage(LargeFileLocal):
+        pass
+
+    configure(
+        tracing_database_factory=CustomDatabase,
+        large_file_implementation=CustomStorage,
+        disable_se4ml_banner=True,
+    )
+    assert isinstance(get_context().tracing_database, CustomDatabase)
+    assert get_context().large_file_implementation is CustomStorage