Expose the existing profile-aware gateway boot reconnect path through a
single-flight renderer action, and surface a Reconnect button in the
gateway status menu panel whenever the socket is not open. Repeated
clicks share one in-flight reconnect; failures surface through the
existing non-destructive notification UI. Localized copy for all
supported Desktop locales.
Salvaged from PR #80694 (net diff re-applied onto current main; panel
code lives in app/shell/gateway-menu-panel.tsx now).
ace85d63de