Add Starlink status lines for the physical gateway pane (closes #3) (#7)

Detection is a TCP connect to the dish endpoint bound to the physical
interface; once a dish answers, get_status is read every 5s and two
status lines render under the physical pane, red on disconnect or
alert. No dish: nothing drawn, no RPC. Minimal vendored proto bindings
for get_status only. Independent review passed (PR 7 comment 100012).

Model: opus-4-8 (implementation and review); model: claude-fable-5
(merge)

internal/cli/root.go

@@ -98,6 +98,11 @@ func runMonitor(cmd *cobra.Command, cfg *config) error {
 
 	mon := monitor.NewMonitor(specs, cfg.LogFile)
 
+	// The non-VPN physical gateway is the last pane: pane B when there are
+	// two, the only pane when there is one. That is where a Starlink dish,
+	// if present upstream, is detected and its status shown.
+	mon.EnableStarlink(specs[len(specs)-1].Name)
+
 	for _, host := range cfg.Hosts {
 		mon.AddReachabilityHost(host)
 	}