[docs-infra] Add Benchmarking Pages to Docs

[dav-is]

Important

For the most accurate benchmarks, you should use a production build in incognito mode

Add a benchmarking page at http://localhost:3000/docs-infra/components/code-highlighter/bench

This page shows the code needed to reproduce the benchmark and a button that opens the bench dialog

Demo code can be opened in a dialog. The demo page is loaded into an iframe which reports web vitals like First Contentful Paint (FCP), Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), Interaction to Next Paint (INP), Time to Interactive (TTI), Total Blocking Time (TBT). Long tasks considered blocking (longer than 50ms) are also logged. After the 5 seconds needed to calculate TTI, the user can interact with the benchmark frame. This is helpful to see if any long tasks are reported.

The benchmark can be opened directly for more advanced profiling at http://localhost:3000/bench/docs-infra/components/code-highlighter/demos/code