Lessons are Russian on the English /guides/<slug>/ route as well

[explosivebit]

What is wrong

The 20 interactive lessons in website/public/guides-raw/*.html are written in Russian, but they are
served on both the English and the Russian route. /guides/<slug>/ and /ru/guides/<slug>/ render
the same Russian paragraph.

Checked on intro: the Russian text is present in both

• dist/guides/intro/index.html
• dist/ru/guides/intro/index.html

Cause

website/src/lib/embed-html.ts (extractEmbed) inlines the body + styles + scripts of the standalone
Russian lesson into whatever page wraps it. There is one file per lesson, so the English wrapper has
nothing English to inline - it embeds the Russian source verbatim. website/src/pages/guides/[slug].astro
builds the EN route from the same public/guides-raw file as the RU route.

Why it was not fixed in the freshness sweep

Translating 20 interactive lessons is authoring work, not drift repair. The sweep that produced this
issue was scoped to documentation that had fallen behind the 0.37 binary and the marketplace
catalogue; rewriting lesson prose belongs to a dedicated pass with its own review.

What was rejected

• Iframing the lessons per locale - iframes were rejected by the owner twice already, and the
  inlining pipeline is deliberate (extractEmbed scopes CSS under .guide-embedded, wraps inline
  scripts in an IIFE, strips the lesson's own footer).
• Hiding the EN route - the guides are reached from /guides and from the blog; removing the
  route breaks inbound links that check-dead-links.mjs currently passes.
• Machine-translating the lessons in this pass - they are interactive, with terminal transcripts
  and figures; a translation without a rendering check would ship broken lessons.

Revisit trigger

Act when either becomes true:

1. the owner wants English-language lessons on the English route, or
2. the English route starts being indexed or advertised as English content - a Russian lesson ranking
   for an English query is worse than no lesson.