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>

tools/__init__.py

@@ -3,6 +3,7 @@ Tool implementations for Gemini MCP Server
 """
 
 from .analyze import AnalyzeTool
+from .chat import ChatTool
 from .debug_issue import DebugIssueTool
 from .review_code import ReviewCodeTool
 from .think_deeper import ThinkDeeperTool
@@ -12,4 +13,5 @@ __all__ = [
     "ReviewCodeTool",
     "DebugIssueTool",
     "AnalyzeTool",
+    "ChatTool",
 ]