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/monitor/ui.go

@@ -107,6 +107,11 @@ func (m *Monitor) DrawInterface(scr tcell.Screen, y, w int, st *InterfaceStatus)
 	y = m.drawTCPTable(scr, y, st, tcpHosts)
 	y = drawICMPStats(scr, y, st)
 
+	// The Starlink lines belong to the physical (non-VPN gateway) pane only.
+	if st == m.slPane {
+		y = m.drawStarlink(scr, y)
+	}
+
 	return y
 }