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/config.py

@@ -22,9 +22,6 @@ class CordraConfig(BaseSettings):
     password: str | None = Field(
         default=None, description="Password for Cordra authentication"
     )
-    max_search_results: int = Field(
-        default=1000, description="Maximum number of search results to return"
-    )
     verify_ssl: bool = Field(
         default=True, description="Whether to verify SSL certificates"
     )