fix: update integration test tool count to 13 (includes generate_report)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: cauchyturing

tests/test_mcp_integration.py

@@ -48,7 +48,7 @@ def test_tool_count(self):
         from causal_copilot.mcp.server import mcp
 
         tools = asyncio.run(mcp.list_tools())
-        assert len(tools) == 12
+        assert len(tools) == 13
 
     def test_mcp_cli_entry(self):
         from causal_copilot.cli import main