fix(builder): escape/allowlist all attribute-value sinks incl. numeric/enum props (XSS)

An adversarial pass found 5 Critical XSS sinks where props declared number/enum
in TypeScript were interpolated raw into exported HTML attribute values,
trusting the type — but nothing enforces it at runtime (AI update_props only
validates node_id; deserialized saved state is untyped JSON). Fixed all 5
(NumberCounter data-target, StarRating aria-label, FormContainer method,
ContactForm/InputField input type) plus 6 sibling sinks found by an exhaustive
audit of every attribute-value interpolation across src/components: a
JS-source injection into ContentSlider's inline setInterval script, a
prototype-pollution-adjacent allowlist gap in Section's divider-shape lookup,
TextareaField rows, Testimonials rating aria-label, HeroSimple textAlign, and
MapEmbed zoom. Adds shared sanitizeFormMethod/sanitizeInputType allowlist
helpers to utils/escape.ts alongside the existing escapeAttr/safeUrl/cssValue
primitives. Every fix is TDD'd: a malicious-value test reproduces the raw
injection against the pre-fix code, then passes after the fix.

502 tests green (npx vitest run), tsc + vite build green (npm run build).

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

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

@@ -0,0 +1,25 @@
+import { describe, test, expect } from 'vitest';
+import { FormButton } from './FormButton';
+
+const toHtml = (FormButton as any).toHtml;
+
+describe('FormButton.toHtml', () => {
+  test('normal text renders as-is', () => {
+    const { html } = toHtml({ text: 'Send it' }, '');
+    expect(html).toContain('>Send it<');
+    expect(html).toContain('type="submit"');
+  });
+
+  test('type="submit" is a hardcoded literal, not prop-driven', () => {
+    const { html } = toHtml({ text: 'Submit' }, '');
+    expect(html).toMatch(/<button type="submit"/);
+  });
+
+  test('text content is escaped for <, >, &, and " (consistent with escapeHtml)', () => {
+    const { html } = toHtml({ text: '<script>alert(1)</script> & "quoted"' }, '');
+    expect(html).not.toContain('<script>');
+    expect(html).toContain('&lt;script&gt;alert(1)&lt;/script&gt;');
+    expect(html).toContain('&amp;');
+    expect(html).toContain('&quot;quoted&quot;');
+  });
+});