Tighten the parse-failure handler: silently ignore postMessage frames
where event.data?.jsonrpc !== "2.0" (i.e. not JSON-RPC at all — null,
undefined, a primitive, or an object from the host environment that
doesn't carry the jsonrpc field). Messages that do carry jsonrpc: "2.0"
but are otherwise malformed still surface via onerror so genuine protocol
errors aren't swallowed.
https://claude.ai/code/session_01DaJpUtSJf4hA7tnu3nJz8s
Co-authored-by: Claude <noreply@anthropic.com>