Retry peer reconnect every 5s until back online

Replace exponential backoff and the 12-attempt cap with a fixed 5s
retry loop that keeps dialing after unexpected disconnects. Throttle
toasts so the UI is not spammed while the offline banner stays up.

ui/ops-app.js

@@ -1526,9 +1526,10 @@ export function initOpsApp({ navigateToView, sendCommand }) {
     }
   })
   manager.on('reconnecting', ({ attempt, delayMs }) => {
+    const secs = Math.max(1, Math.round((delayMs || 5000) / 1000))
     setOfflineBanner(
       true,
-      `Connection lost — reconnecting (attempt ${attempt}) in ${Math.round(delayMs / 1000)}s…`
+      `Connection lost — retrying every ${secs}s (attempt ${attempt})…`
     )
   })
   manager.on('reconnected', () => {