feat(ui,server): surface active instance service URLs in About settings (#2669)

Show the running instance's local server URL and tunnel URL (when a
tunnel is active) as labeled, click-to-open buttons on the About page.
/api/system/info now reports the instance port and tunnel URL, resolved
lazily from the tunnel runtime so each Git-worktree instance identifies
itself in the UI without parsing terminal output.

Refs OPE-194

packages/ui/src/lib/i18n/messages/de.settings.ts

@@ -445,6 +445,9 @@ export const settingsDict = {
   'settings.openchamber.about.title': 'Über OpenChamber',
   'settings.openchamber.about.field.version': 'Version',
   'settings.openchamber.about.field.openCodeVersion': 'OpenCode-Version',
+  'settings.openchamber.about.field.instanceUrls': 'Instanz-URLs',
+  'settings.openchamber.about.field.applicationUrl': 'Anwendung',
+  'settings.openchamber.about.field.tunnelUrl': 'Tunnel',
   'settings.openchamber.about.state.checking': 'Wird geprüft...',
   'settings.openchamber.about.state.upToDate': 'Aktuell',
   'settings.openchamber.about.state.unknown': 'unbekannt',