Pick up deployments after a station reconnects

A station that was offline when a deployment was pushed kept running the previous deployment after it came back online: the dashboard's deployment command is sent once, and a station whose link was down never received it. The dashboard showed the new deployment as ready while runs kept using the old one.

• Added a deployment check every time the station's dashboard link comes up, on start and after every reconnect; when nothing changed it is a single request
• Fixed the station not noticing a dropped dashboard link, so "Connection lost" and "Reconnected" now show on a real drop and telemetry pauses while the link is down
• A check that lands during a run is staged and applied between runs, as for a deployment pushed from the dashboard