Add public repository interfaces and subclassable adapter CRUD API.

Define split JSON and object repository ABCs, promote adapter methods to public CRUD, add example domain repositories, modernize interface stubs, and make the package installable for tests.

Co-authored-by: Cursor <[email protected]>

python_repositories/interfaces/connection_aware_interface.py

@@ -9,15 +9,15 @@ class ConnectionAwareInterface(ABC):
     @abstractmethod
     def connect(self) -> None:
         """Connect to resource."""
-        raise NotImplementedError()
+        ...
 
     @abstractmethod
     def disconnect(self) -> None:
         """Disconnect from resource."""
-        raise NotImplementedError()
+        ...
 
     @property
     @abstractmethod
     def is_connected(self) -> bool:
         """Check if connected to resource."""
-        raise NotImplementedError()
+        ...