[react-devtools-cdt-mcp] add chrome-devtools E2E coverage (#36823)

A node runner that bootstraps `fixtures/app`, and then uses
`chrome-devtools` CLI to test third-party tools.

```
$ node e2e/run.js
Starting fixture at http://127.0.0.1:60033/
Starting chrome-devtools daemon...
Checking third-party tool discovery...
Checking tree, details, search, and DOM lookup...
Checking source, owners, and error payloads...
Checking profiling through a real CLI click...
react-devtools-cdt-mcp E2E passed.
✨  Done in 11.66s.
```