refactor: remove unused max_search_results config parameter

The max_search_results configuration parameter was only used in one
location and added unnecessary complexity. Search operations now use
a consistent default page size of 20, which aligns with the pagination
implementation and provides better user experience.

Changes:
- Remove max_search_results from CordraConfig
- Update search_objects to use default page size of 20
- Simplify tests by removing config mocking
- Maintain backward compatibility through limit parameter

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/cordra_mcp/server.py

@@ -56,8 +56,9 @@ async def search_objects(
         JSON string containing list of matching objects with their full metadata
     """
     try:
-        effective_limit = limit if limit is not None else config.max_search_results
-        search_result = await cordra_client.find(query, object_type=type, page_size=effective_limit)
+        # Use provided limit or default page size of 20
+        page_size = limit if limit is not None else 20
+        search_result = await cordra_client.find(query, object_type=type, page_size=page_size)
         results = search_result["results"]
         return json.dumps(results, indent=2)