feat: add Claude-Gemini collaboration and chat capabilities

- Add collaboration demo showing dynamic context requests
- Implement chat tool for general conversations and brainstorming
- Add tool selection guide with clear boundaries
- Introduce models configuration system
- Update prompts for better tool descriptions
- Refactor server to remove redundant functionality
- Add comprehensive tests for collaboration features
- Enhance base tool with collaborative features

This enables Claude to request additional context from Gemini
during tool execution, improving analysis quality and accuracy.

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

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

tests/test_server.py

@@ -61,7 +61,12 @@ class TestServerTools:
             result = await handle_call_tool("chat", {"prompt": "Hello Gemini"})
 
             assert len(result) == 1
-            assert result[0].text == "Chat response"
+            # Parse JSON response
+            import json
+
+            response_data = json.loads(result[0].text)
+            assert response_data["status"] == "success"
+            assert response_data["content"] == "Chat response"
 
     @pytest.mark.asyncio
     async def test_handle_list_models(self):