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/components/sections/openchamber/AboutSettings.tsx

@@ -9,6 +9,7 @@ import { Icon } from "@/components/icon/Icon";
 import { OpenChamberLogo } from '@/components/ui/OpenChamberLogo';
 import { useI18n } from '@/lib/i18n';
 import { runtimeFetch } from '@/lib/runtime-fetch';
+import { InstanceServiceUrls } from './InstanceServiceUrls';
 import {
   SettingsSection,
   SETTINGS_BRAND_TITLE_CLASS,
@@ -135,6 +136,7 @@ export const AboutSettings: React.FC<AboutSettingsProps> = ({ initialUpdateDialo
             <p>{t('aboutDialog.openChamberVersionLabel', { version: currentVersion })}</p>
             <p>{t('aboutDialog.openCodeVersionLabel', { version: openCodeVersion || t('settings.openchamber.about.state.unknown') })}</p>
           </div>
+          <InstanceServiceUrls />
         </div>
 
         <div className="flex justify-center">
@@ -278,6 +280,11 @@ export const AboutSettings: React.FC<AboutSettingsProps> = ({ initialUpdateDialo
           </div>
         )}
 
+        <div className="flex flex-col gap-2 border-b border-border/40 px-4 py-3 @xl:flex-row @xl:items-center @xl:justify-between">
+          <span className={SETTINGS_FIELD_LABEL_CLASS}>{t('settings.openchamber.about.field.instanceUrls')}</span>
+          <InstanceServiceUrls />
+        </div>
+
         <div className="flex items-center gap-4 px-4 py-4">
           <a
             href={GITHUB_URL}

packages/ui/src/components/sections/openchamber/InstanceServiceUrls.tsx

@@ -0,0 +1,106 @@
+import React from 'react';
+import { useI18n } from '@/lib/i18n';
+import { runtimeFetch } from '@/lib/runtime-fetch';
+import { openExternalUrl } from '@/lib/url';
+import { Button } from '@/components/ui/button';
+import { Icon } from '@/components/icon/Icon';
+
+type InstanceServiceInfo = {
+  port: number | null;
+  tunnelUrl: string | null;
+};
+
+type InstanceService = {
+  key: string;
+  label: string;
+  url: string;
+};
+
+/**
+ * Shows the active instance's service URLs (local server port + tunnel URL,
+ * when a tunnel is active) as labeled buttons that open the URL in the
+ * browser. The data comes from `/api/system/info`, which the server derives
+ * from its own runtime state — this is what makes each Git-worktree instance
+ * distinguishable in the UI without reading terminal output.
+ *
+ * The section stays hidden when the endpoint is unavailable or reports no
+ * port/tunnel (e.g. VS Code runtime), so a failed fetch never renders stale
+ * or wrong URLs.
+ */
+export const InstanceServiceUrls: React.FC = () => {
+  const { t } = useI18n();
+  const [info, setInfo] = React.useState<InstanceServiceInfo | null>(null);
+
+  React.useEffect(() => {
+    let cancelled = false;
+    const controller = typeof AbortController !== 'undefined' ? new AbortController() : undefined;
+
+    const load = async () => {
+      try {
+        const response = await runtimeFetch('/api/system/info', {
+          signal: controller?.signal,
+          headers: { Accept: 'application/json' },
+        });
+        if (!response.ok) return;
+        const data = await response.json().catch(() => null) as { port?: unknown; tunnelUrl?: unknown } | null;
+        if (!data || cancelled) return;
+        const port = typeof data.port === 'number' && Number.isFinite(data.port) && data.port > 0 ? data.port : null;
+        const tunnelUrl = typeof data.tunnelUrl === 'string' && data.tunnelUrl.trim().length > 0
+          ? data.tunnelUrl.trim()
+          : null;
+        setInfo({ port, tunnelUrl });
+      } catch {
+        // Best-effort: a failed fetch keeps the section hidden instead of
+        // showing data we cannot verify.
+      }
+    };
+
+    void load();
+
+    return () => {
+      cancelled = true;
+      controller?.abort();
+    };
+  }, []);
+
+  const services: InstanceService[] = [];
+  if (info?.port !== null && info?.port !== undefined) {
+    services.push({
+      key: 'application',
+      label: t('settings.openchamber.about.field.applicationUrl'),
+      url: `http://localhost:${info.port}/`,
+    });
+  }
+  if (info?.tunnelUrl) {
+    services.push({
+      key: 'tunnel',
+      label: t('settings.openchamber.about.field.tunnelUrl'),
+      url: info.tunnelUrl,
+    });
+  }
+
+  if (services.length === 0) {
+    return null;
+  }
+
+  return (
+    <div className="flex flex-wrap items-center gap-2">
+      {services.map((service) => (
+        <Button
+          key={service.key}
+          type="button"
+          variant="outline"
+          size="sm"
+          title={service.label}
+          className="max-w-full gap-1.5 px-2.5"
+          onClick={() => {
+            void openExternalUrl(service.url);
+          }}
+        >
+          <Icon name="external-link" className="size-3.5 shrink-0" />
+          <span className="max-w-64 truncate font-mono typography-micro">{service.url}</span>
+        </Button>
+      ))}
+    </div>
+  );
+};