feat: Add haptic feedback for number, decimal, and backspace

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

calculator/calculator.app.js

@@ -554,6 +554,7 @@ function buttonPress(val) {
       }
       break;
     case 'B':
+      Bangle.buzz();
       if (isDecimal) {
         isDecimal = false;
         displayOutput(currNumber);
@@ -584,6 +585,7 @@ function buttonPress(val) {
       if (swipeEnabled) drawNumbers();
       break;
     case '.':
+      Bangle.buzz();
       specials.R.val = 'C';
       if (!swipeEnabled) drawKey('R', specials.R);
       isDecimal = true;
@@ -644,6 +646,7 @@ function buttonPress(val) {
       }
       break;
     default: {
+      Bangle.buzz();
       specials.R.val = 'C';
       if (!swipeEnabled) drawKey('R', specials.R);
       const is0Negative = (currNumber === 0 && 1/currNumber === -Infinity);