extend documentation

[tb102122]

Hey all,

I think it would be helpful to add a note for python deployments with packaging via Lambda Layers.
The startup command needs to be extended:

import sys
# Add Lambda Layers to subprocess environment
lambda_paths = ["/opt/python"] + sys.path
env_config = {"PYTHONPATH": ":".join(lambda_paths)}

server_params = StdioServerParameters(
    command=sys.executable,
    args=[
        "-c",
        "from mcp_openapi_proxy import main; main()",
    ],
    env=env_config,
)