feat(client): opt-in "Rumble on this phone" mirrors pad-0 rumble onto the device

iOS + Android: a new opt-in setting mirrors controller 1's rumble onto the
device's own actuator (Apple RumbleRenderer Actuator.device / CoreHaptics,
Android deviceBodyVibrator), so a motor-less clip-on pad still gives haptic
feedback through the phone/tablet it's clamped to. Default off; wired through
the gamepad settings on both platforms.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/apple/Sources/PunktfunkClient/Settings/SettingsView.swift

@@ -55,6 +55,7 @@ struct SettingsView: View {
     #if os(iOS)
     @AppStorage(DefaultsKey.pointerCapture) var pointerCapture = true
     @AppStorage(DefaultsKey.touchMode) var touchMode = TouchInputMode.trackpad.rawValue
+    @AppStorage(DefaultsKey.rumbleOnDevice) var rumbleOnDevice = false
     // The sidebar selection drives the detail pane on iPad and the pushed sub-page on iPhone.
     // Width class decides the initial value: nil on iPhone (show the category list first),
     // General on iPad (a two-column layout should never open with an empty detail).