A fresh ACP agent appended mcp-<server> for every enabled config MCP server
unconditionally, so a platform_toolsets.acp allowlist of server names and the
no_mcp sentinel were ignored on ACP while the gateway honoured both.
The MCP half now comes from the same _get_platform_tools(config, "acp") call
as the base toolsets: its server names (default every enabled server, a listed
allowlist, or none for no_mcp) are keyed as mcp-<server>. Editor-provided
session/new servers are unchanged.
Docs: `hermes tools` has no ACP platform entry, so drop the claim that it
configures platform_toolsets.acp; document the MCP rules with a config example.