chore: initial padel scaffold + design docs

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

source/garmin-padelMenuDelegate.mc

@@ -0,0 +1,19 @@
+import Toybox.Lang;
+import Toybox.System;
+import Toybox.WatchUi;
+
+class garmin_padelMenuDelegate extends WatchUi.MenuInputDelegate {
+
+    function initialize() {
+        MenuInputDelegate.initialize();
+    }
+
+    function onMenuItem(item as Symbol) as Void {
+        if (item == :item_1) {
+            System.println("item 1");
+        } else if (item == :item_2) {
+            System.println("item 2");
+        }
+    }
+
+}