fix(mcp): add MCP_PROTOCOL_VERSION alias to protocol module

Adds MCP_PROTOCOL_VERSION as an alias for PROTOCOL_VERSION so that
existing tests importing MCP_PROTOCOL_VERSION continue to work.

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

Author: tmgbedu

fastapi_startkit/src/fastapi_startkit/mcp/protocol.py

@@ -11,6 +11,7 @@
     from .resource import Resource
 
 PROTOCOL_VERSION = "2024-11-05"
+MCP_PROTOCOL_VERSION = PROTOCOL_VERSION
 
 
 class Protocol: