feat(builder): FORMS package -- field editor, functional Subscribe/Search, box-model+anim rollout

- FormStylePanel: ContactForm field editor (add/remove/reorder via
  ArrayPropEditor + manual move up/down) covering label/name/placeholder/
  type (full sanitizeInputType allowlist + textarea/select)/required/
  options.
- SubscribeForm.toHtml: was a dead `<form method="POST">` with no action at
  all -- wired through the same relayFormWiring contract as ContactForm/
  FormContainer so a recipientEmail makes it actually submit (marker +
  placeholder action + honeypot), falling back to action="#" otherwise.
- SearchBar: was purely decorative (no action/method/input name) -- now a
  real GET form (configurable target, default "/") with input name="q",
  safeUrl-guarded against javascript:/vbscript: breakout.
- Box-model (margin/padding per-side, border, shadow, opacity), entrance
  animation, and hide-on-device controls added to FormStylePanel and
  rolled out (blank/false craft.props defaults) across ContactForm,
  FormContainer, InputField, TextareaField, FormButton, SubscribeForm,
  SearchBar. No toHtml changes needed for animation/visibility --
  html-export.ts's buildDataAttrs() already emits data-animation/
  data-hide-* generically from these prop names.
- Extended toHtml tests for all 7 components: field-type rendering
  (incl. textarea/select), type-attribute XSS sanitization, relay/GET
  functional wiring, box-model style passthrough, craft.props defaults.

npx vitest run: 689/689 passed. npm run build: green.

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

craft/src/components/forms/TextareaField.toHtml.test.ts

@@ -63,3 +63,20 @@ describe('TextareaField.toHtml rows attribute sanitization', () => {
     expect(html).toContain('rows="8"');
   });
 });
+
+describe('TextareaField.toHtml box-model style passthrough', () => {
+  test('margin/border/box-shadow/opacity flow through via the style prop', () => {
+    const { html } = toHtml({ label: 'Message', name: 'message', style: { marginTop: '10px', border: '1px solid #555', boxShadow: '0 1px 3px rgba(0,0,0,.15)', opacity: '0.7' } }, '');
+    expect(html).toContain('margin-top:10px');
+    expect(html).toContain('border:1px solid #555');
+    expect(html).toContain('opacity:0.7');
+  });
+});
+
+describe('TextareaField.craft.props includes animation/visibility defaults', () => {
+  test('has blank/false defaults', () => {
+    expect(TextareaField.craft!.props).toMatchObject({
+      animation: '', animationDelay: '', hideOnDesktop: false, hideOnTablet: false, hideOnMobile: false,
+    });
+  });
+});