Get the MCP remote server URL for a specific connection ID. Returns a ready-to-use, connection-scoped Streamable HTTP MCP endpoint that exposes that connection's integration-specific tools. Authenticate with a workspace API key to use this. The URL embeds a credential and grants tool access without a further login, so treat it as a secret. It does NOT expire on its own. Revocation depends on the mode (see the `mode` parameter): an 'api'-mode URL carries the workspace API key and is revoked by rotating that key (which affects every URL that used it); a 'user'-mode URL is scoped to this one connection and is revoked by deleting the connection. Optional server options (permissions, tools, aliases, defer_tools, hide_sensitive, include_external_tools) are baked into the returned URL as query parameters.