docs: translate current documentation and site UI into Ukrainian

[rmcdaniel]

Scope

Complete #161: Ukrainian current documentation and site UI, with English as the default locale. Blogs and versioned 1.x documentation retain the English fallback.

Changes

• Ukrainian locale at /uk/, language switcher, navigation, footer, search labels and theme messages.
• All 102 current documentation pages and category metadata translated, along with the homepage, Temporal comparison, CLI installer, protocol tables and interactive simulators.
• Localized edit links and contributor translation instructions.
• Unicode-preserving search tokenization, with regression coverage for Ukrainian terms, English API names and serialized index reload.
• Corrected outdated English guidance encountered during translation, including cancellation and parent-close policies, worker capabilities and runtime registration, sample history/MCP examples, v1 adoption links, drain intent and per-queue flow counters. Cloud HA plans are described as in qualification and unavailable to purchase or provision, matching live pricing. The separately versioned Helm path is linked from Server deployment guidance, and Python's health endpoint is identified as liveness.

Verification

• All 645 fenced code blocks and 1,029 heading anchors in the 102 translated docs match their current English sources. The comparison preserves both code blocks and all 10 heading anchors.
• Fresh dependency installation applied all three patches. The Unicode search regression passed. Search inputs also expose translated accessible labels.
• Clean English and Ukrainian production build passed with strict Markdown, link and anchor checks enabled. Documentation Qualification, Public Boundary and Protocol Specs all passed at 8e2e0ad327ff39a649ffec863bb6f9d250f6e688.
• Browser checks passed for Ukrainian search, Markdown navigation, locale switching in both directions, the Temporal comparison, CLI installer platform selection, timer simulator, homepage and mobile rendering. No browser runtime exceptions.
• npm run start -- --locale uk served the translated introduction with HTTP 200 and html lang="uk".
• Reviewed the locale routing, component translations, dependency patches and search regression. Git whitespace check passed.

Publication

After merge, verify published Ukrainian routes and locale switching, then close #161. Strict broken-link and broken-anchor checks stay enabled.