Use dict[str, Any] for JSON repository document types.

Clarifies that JSON CRUD operates on string-keyed objects without changing runtime behavior.

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

README.md

@@ -123,16 +123,18 @@ with ArtifactObjectRepository() as repo:
 ### Subclassing in your own project
 
 ```python
+from typing import Any
+
 from python_repositories import RedisAdapter
 
 class UserRepository(RedisAdapter):
     def _key(self, user_id: str) -> str:
         return f"user:{user_id}"
 
-    def get_user(self, user_id: str) -> dict | None:
+    def get_user(self, user_id: str) -> dict[str, Any] | None:
         return self.get(self._key(user_id))
 
-    def save_user(self, user_id: str, user: dict) -> None:
+    def save_user(self, user_id: str, user: dict[str, Any]) -> None:
         self.set(self._key(user_id), user)
 ```