docs: add SSH hosts and proxying guide

Adds desktop SSH hosts and proxying documentation
Includes translations for all supported locales
Requires translations for new docs pages

packages/docs/CONTRIBUTING.md

@@ -98,9 +98,8 @@ running.
    - `foo.mdx` -> `/foo/`
    - `folder/index.mdx` -> `/folder/`
    - `folder/bar.mdx` -> `/folder/bar/`
-4. Add translations for the page — see [Localization](#localization). Translations
-   are optional per page (a missing translation falls back to English), but ship
-   them together with the page when you can.
+4. Add translations for the page — see [Localization](#localization). New pages
+   must include translated files for every supported locale before they ship.
 5. If the page is linked from the sidebar, add its localized labels too — see
    [Translate the sidebar](#translate-the-sidebar).
 6. Run validation:
@@ -244,9 +243,9 @@ description: Встановіть OpenChamber для десктопа, вебу
 ---
 ```
 
-You do **not** have to translate every page at once. A page that is missing in a
-locale automatically falls back to the English version, so translations can land
-incrementally.
+Every new page must include translated files for all supported locales before it
+ships. Starlight can fall back to English when a translation is missing, but do
+not rely on that fallback for new docs pages.
 
 ### Translate the sidebar