Multi-Language Sites [DONE] `PL-F1809`

Multi-language support is built into the CmsPage model. Each page has a base language (`source_language`) and a translations map keyed by ISO locale (`sv`, `fr`, `de`, …) containing localized title, slug, meta and a translated copy of the block array. The CmsSite declares supported_languages and default_language; pages can be translated into any subset of the site's supported list, and partial coverage is allowed — pages without a target translation fall back to default with a polite notice for visitors who chose another language.

Localized URLs follow a `/<locale>/...` pattern except the default language, which uses clean root paths to keep canonical URLs stable. The renderer detects visitor language via the URL prefix first, then Accept-Language headers, then a sessionStorage preference; the language switcher in the navigation lets visitors change explicitly and remembers the choice across pages. The translation workflow surfaces a queue per site: when a source page is updated, every translation is automatically flagged 'needs review' with a diff against the previous source version, so translators see exactly what changed.

Translators can be different OrgNodeMembers from editors and have a `cms:translate` capability that lets them edit translations without unlocking the source. SEO hreflang tags are emitted for every available translation plus an `x-default` pointing to the site default; the sitemap includes `xhtml:link` hreflang alternates so Google indexes each language correctly. CMS-search respects the active locale and only returns results from the matching language version, with a setting to fall back to default-language matches when no localized hit exists.