docs: optimizing-user-experience tutorial needs a public, current example site

[markdumay]

Tracks a follow-up to the styles-pipeline docs refresh (gethinode.com PR #168). The tutorial content lives in the gethinode.com repo (content/tutorials/optimizing-user-experience/index.md), which has issues disabled, so tracking it here.

Problem

The optimizing-user-experience tutorial demonstrates CSS purging / performance optimization by cloning a real Hinode site. Its clone target is no longer usable:

• It originally cloned gethinode/docs, now archived (and pinned to an old, pre-v3.6 Hinode — so it wouldn't demonstrate the current purge-by-default pipeline).
• gethinode.com PR Bump rimraf from 4.3.0 to 4.3.1 #168 changed it to gethinode/gethinode.com, but that repo is now private — readers can't clone it.

We need a public, current Hinode site as the worked example — likely Hinode's example site (exampleSite/ in this repo), or the gethinode/template starter, or a small dedicated public example repo.

Scope of the rework (beyond swapping the clone URL)

• Clone command + prerequisites — must be a public repo a reader can clone and npm run start (the exampleSite/ isn't independently cloneable as-is; consider the template or a dedicated example).
• Baseline numbers — currently "~400KB main.css". Since v3.6 the default is purged; the tutorial disables purge to show the unpurged baseline (~576KB on the docs site). Re-measure for the chosen example.
• Screenshots in img/ (Chrome DevTools, Lighthouse) currently show the docs site.
• Production step — "Visit https://gethinode.com … Brotli/content-encoding" assumes the public docs site; pick a public deployed example (e.g. https://demo.gethinode.com).
• The example must be content-rich enough to show a meaningful purge delta (a minimal template site purges less dramatically).

Context

The v3.6 factual corrections (purge default on, hugo_stats.json gitignored, curated safelist, cssnano default preset) are already handled in gethinode.com PR #168 — this issue tracks only the remaining example-site rework. #168's interim clone line (gethinode.com, now private) should be replaced as part of this work.

[markdumay]

Update: gethinode.com PR #168 no longer points at the private gethinode.com. Its interim clone target has been reverted to the archived-but-still-public gethinode/docs, so the tutorial's clone command works again in the meantime. This issue still tracks the proper rework — moving to a current public example (Hinode's example site / template) and re-basing the baseline numbers and screenshots on it.