FIX: Migrate MCP server notebook example from v1 to v2 API and fix path

[Justin Song (jsong468)]

Description

• Fixed the notebook’s MCP config path so it resolves relative to the notebook directory for all users (root cause of integration test failure)
• Migrated the example notes server from the MCP 1.x FastMCP API to the MCP 2.x MCPServer API. This includes a rename from FastMCP to MCPServer and transport-specific parameters moving from MCPServer constructor to run() method. See here
• Preserved support for both standalone HTTP and automatically managed stdio transports.

Tests and Documentation

Re-ran failing notebook cell