dashboard: show GATEWAY_HEALTH_URL instead of PID for remote gateways

When the dashboard connects to a remote gateway via GATEWAY_HEALTH_URL,
display the URL instead of the remote PID (which is meaningless locally).
Falls back to PID display for local gateways as before.

- Backend: expose gateway_health_url in /api/status response
- Frontend: prefer gateway_health_url over PID in gatewayValue()
- Add truncate + title tooltip for long URLs that overflow the card
- Add min-w-0/overflow-hidden on status cards for proper truncation
- Tests: verify gateway_health_url in remote and no-URL scenarios

hermes_cli/web_server.py

@@ -467,6 +467,7 @@ async def get_status():
         "latest_config_version": latest_ver,
         "gateway_running": gateway_running,
         "gateway_pid": gateway_pid,
+        "gateway_health_url": _GATEWAY_HEALTH_URL,
         "gateway_state": gateway_state,
         "gateway_platforms": gateway_platforms,
         "gateway_exit_reason": gateway_exit_reason,