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/json_repository_interface.py

@@ -0,0 +1,27 @@
+"""Definition of JsonRepositoryInterface abstract base class."""
+
+from abc import ABC, abstractmethod
+
+
+class JsonRepositoryInterface(ABC):
+    """Interface that defines JSON document CRUD methods."""
+
+    @abstractmethod
+    def get(self, key: str) -> dict | None:
+        """Get a JSON object by key."""
+        ...
+
+    @abstractmethod
+    def set(self, key: str, data: dict) -> None:
+        """Set a JSON object by key."""
+        ...
+
+    @abstractmethod
+    def delete(self, key: str) -> None:
+        """Delete a JSON object by key."""
+        ...
+
+    @abstractmethod
+    def list_keys(self, pattern: str) -> list[str]:
+        """List keys matching a glob pattern."""
+        ...