Add a streamable-HTTP MCP adapter (mcp_server.py, official FastMCP SDK)
mounted at /mcp in the existing FastAPI app, with a combined lifespan so
the MCP session manager starts/stops with the service. Ships one smoke
tool (qonto_ping, no bank call) — real capability tools land in T02.
Prove REST and MCP hit the identical policy path: PolicyEngine.decide()
never branches on request.protocol, verified by a parametrized test.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
