feat(sidebar): add compliance scanner link from env config

Read COMPLIANCE_SCANNER_URL from environment via ServiceUrls config and
surface it through AuthInfo to the sidebar. The link renders with a
shield icon and opens in a new tab, only when the URL is configured.
Includes i18n translations for all five locales.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/app_shell.rs

@@ -76,6 +76,7 @@ pub fn AppShell() -> Element {
                         name: info.name,
                         avatar_url: info.avatar_url,
                         librechat_url: info.librechat_url,
+                        compliance_scanner_url: info.compliance_scanner_url,
                         class: sidebar_cls,
                         on_nav: move |_| mobile_menu_open.set(false),
                     }