Fix bilingual content, accessibility and site metadata

[besendorf]

The German and English pages now present consistent professional copy and navigation. German-only posts are linked as originals from the English blog and search, with redirects preserving their former English URLs.

Changes:

• Localize navigation, search, footer, dates and accessibility labels; replace the mobile checkbox menu with a keyboard-accessible native menu and add focus indicators and a skip link.
• Correct page descriptions, social preview assets, favicons, language metadata, RSS and structured data (Person for the home page, BlogPosting only for posts).
• Add local topic, language and text filters to all 70 press entries, selected coverage and 24 publication dates verified against publisher metadata. Keep the complete archive readable without JavaScript.
• Fix pasted-query search and keyboard navigation, render results with safe DOM text, and report loading failures.
• Polish German and English content and preserve literal gender asterisks and historic quotations.
• Keep contact addresses obfuscated: no plaintext emails, mailto links, schema email fields or scripts reconstructing addresses.
• Pin Hugo 0.167.0 and add generated-site validation and interaction tests to CI.

WonderMod was checked against upstream master on 6 October 2026. The existing submodule commit 3b0ee00eb05135a162fdb83de65576b968bab4f0 is still the latest; there is no newer theme revision to install. Compatibility fixes use project overrides.

Validation:

hugo --minify --panicOnWarning
python3 scripts/check_site.py public
node --test tests/*.test.cjs

The build completes without warnings; checks pass for 26 generated HTML pages, local links and fragments, assets, XML, metadata, language handling, archive completeness and email obfuscation. All six search/filter tests pass. A browser preview was blocked by the preview browser, so visual browser testing remains unverified.

Prepared with Codex. This PR does not deploy the site until merged.