Bidirectional custom (non-spec) JSON-RPC methods: the server handles a vendor-prefixed acme/search request via server.setRequestHandler and emits acme/searchProgress notifications via ctx.mcpReq.notify; the client sends the typed request via
client.request(method, schema) and receives the typed notifications via client.setNotificationHandler('acme/searchProgress', { params }).
pnpm tsx examples/custom-methods/client.ts