feat: generate and verify MSIX registry hives

Closes #3

src/apps/desktop/tests/registry-editor.test.mjs

@@ -0,0 +1,24 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { newRegistryEntry, renderRegistryEditor } from '../src/registry-editor.ts';
+
+test('new entries select the app view and preserve lossless text data', () => {
+  assert.equal(newRegistryEntry('x86', 'one').view, '32');
+  const entry = newRegistryEntry('x64', 'two');
+  entry.valueType = 'REG_QWORD'; entry.data = '18446744073709551615';
+  assert.match(renderRegistryEditor([entry], false), /18446744073709551615/);
+  assert.equal(JSON.parse(JSON.stringify(entry)).data, entry.data);
+});
+test('registry editor escapes markup and addresses rows after deletion', () => {
+  const first = newRegistryEntry('x64', 'first');
+  const second = newRegistryEntry('x64', 'second');
+  second.data = '</textarea><script>alert(1)</script>';
+  second.name = '" onfocus="bad';
+  const entries = [first, second]; entries.splice(0, 1);
+  const html = renderRegistryEditor(entries, true);
+  assert.ok(!html.includes('<script>'));
+  assert.ok(html.includes('&lt;/textarea&gt;'));
+  assert.ok(html.includes('&quot; onfocus=&quot;bad'));
+  assert.ok(html.includes('registry.0.data'));
+  assert.ok(html.includes('data-action="registry-remove:0" disabled'));
+});