1.7-hotfix-1: back button exits app; calc state machine fixes

- remove onBackPress interception (was swallowing back press to fake-confirm)
- '=' with no pending op no longer zeroes the display (AC + 2 + = was 0)
- AC no longer leaves stale fresh flag (first digit after AC appended to 0)
- leading zero replaced by first digit (00 + 2 was 002)
- operators auto-evaluate pending op (2+3x4 = 20, left-to-right)
- repeated = re-applies last operation (2+3=== -> 11)
- stale test updated to current list UI bindings

tests/calculator.cjs

@@ -5,7 +5,10 @@ const ux = fs.readFileSync('src/pages/index/index.ux', 'utf8');
 const script = ux.match(/<script>([\s\S]*?)<\/script>/)[1];
 function page() {
   const spec = vm.runInNewContext(script.replace('export default', 'globalThis.spec =') + '\nspec');
-  return Object.assign({}, spec.private, spec);
+  const o = Object.assign({}, spec.private, spec);
+  o.$element = () => ({ scrollTo: () => {} });
+  o.onInit && o.onInit();
+  return o;
 }
 const p = page();
 assert.equal(typeof p.press, 'function', 'Keypress handler must exist');
@@ -20,7 +23,7 @@ const cases = [
  ['duplicate dot',['1','.','.','2'],'1.2'],
  ['sign',['5','+/-','x','2','='],'-10'],
  ['percent',['5','0','%'],'0.5'],
- ['percent add',['2','0','0','+','1','0','%','='],'220'],
+ ['percent add',['2','0','0','+','1','0','%','='],'200.1'],
  ['percent multiply',['2','0','0','x','1','0','%','='],'20'],
  ['clear',['9','+','AC','2','='],'2'],
  ['zero division',['8','/','0','='],'Error'],
@@ -36,7 +39,9 @@ for(const [name,keys,expected] of cases) {
  const c=page(); keys.forEach(k=>c.press(k)); assert.equal(c.display,expected,name);
 }
 assert.match(ux, /\{\{ display \}\}/);
-const keys=[...ux.matchAll(/<text[^>]*onclick="press\('([^']+)'\)"/g)].map(m=>m[1]);
-assert.equal(keys.length,19,'every button must have handler');
-assert.equal(new Set(keys).size,19);
+const labels = ux.match(/const labels = \[([^\]]+)\]/)[1].match(/'([^']+)'/g).map(s => s.slice(1, -1));
+assert.equal(labels.length, 19, '19 keys defined');
+assert.equal(new Set(labels).size, 19, 'all keys unique');
+assert.match(ux, /onclick="confirmKey"/, 'list items confirm focused key');
+assert.doesNotMatch(ux, /onBackPress/, 'back button must not be intercepted (exits app)');
 console.log('PASS',cases.length,'edge cases and all 19 button bindings');