fix: add node button visibility, fix node-guardian swapper health check, fix banner URL transform

scripts/node-guardian-loop.py

@@ -205,7 +205,9 @@ class NodeGuardian:
                 r = await self.client.get(f"{swapper_url}/health", timeout=3.0)
                 if r.status_code == 200:
                     health_data = r.json()
-                    metrics["swapper_healthy"] = health_data.get("status") == "healthy"
+                    # Swapper can return "status": "healthy" or "ok"
+                    status = health_data.get("status", "").lower()
+                    metrics["swapper_healthy"] = status in ("healthy", "ok")
                 else:
                     metrics["swapper_healthy"] = False
             except Exception: