chore: restructured project, updated readme

src/services/__init__.py

@@ -0,0 +1,16 @@
+"""External service integrations and API clients."""
+
+from .catalogue import Catalogue
+from .sru import SWB
+from .lehmanns import LehmannsClient
+from .zotero import ZoteroController
+from .webrequest import BibTextTransformer, WebRequest
+
+__all__ = [
+    "Catalogue",
+    "SWB",
+    "LehmannsClient",
+    "ZoteroController",
+    "BibTextTransformer",
+    "WebRequest",
+]