AU-002: Show reconnecting UI state in device_screen.dart

Track: 1 — MVP
Section: 1.21 BLE Auto-Reconnect
Status: [ ] Todo
Repo: app-user
Branch: feature/AU-002-reconnecting-ui

Done When

Device screen shows "Reconnecting..." with spinner during retry. Shows "Connected" on success, "Disconnected" with manual reconnect button after timeout

Notes

No notes yet.