dashboard: externalize service URLs and network config (Sprint 03 config externalization)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dashboard/backend/routers/system.py

@@ -149,3 +149,13 @@ def openclaw_token(request: Request):
     if not config.is_lan_ip(ip):
         raise HTTPException(status_code=403, detail="Access denied")
     return {"token": OPENCLAW_GATEWAY_TOKEN}
+
+
+@router.get("/external-services")
+def external_services():
+    """Return external service URLs and network config for the frontend sidebar."""
+    return {
+        "lan_ip": config.LAN_IP,
+        "ts_ip": config.TS_IP,
+        "services": config.EXTERNAL_SERVICES,
+    }