Control panel: TAB focus follows on-screen cab order

controllableCabs() enumerated world.elevators (insertion order) while
the panels render world.sortedElevators (local-first, then by label), so
TAB advanced FOCUSED CAB to the next cab in insertion order rather than
the one visually below. Walk sortedElevators so focus moves down the
list as displayed.

Author: douglas-carmichael

Sources/ElevatorSystem/Views/ControlPanelWindow.swift

@@ -123,8 +123,11 @@ struct ControlPanelWindow: View {
     private func controllableCabs() -> [Elevator] {
         // Any cab we can drive -- locally owned, or remote with a live
         // link to its owner. The keyboard focus ring walks this set so
-        // the number / O / C keys can dispatch remote cabs too.
-        world.elevators.filter { network.canControl($0) }
+        // the number / O / C keys can dispatch remote cabs too. Use the
+        // SAME order the panels are rendered in (sortedElevators), so TAB
+        // advances "FOCUSED CAB" to the cab visually below the current one
+        // rather than to the next cab in raw insertion order.
+        world.sortedElevators.filter { network.canControl($0) }
     }
 
     private func ensureFocus() {