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/media/VideoBlock.toHtml.test.ts

@@ -72,6 +72,38 @@ describe('VideoBlock.toHtml iframe accessibility (F2.4)', () => {
   });
 });
 
+describe('VideoBlock.toHtml overlay/innerMaxWidth XSS hardening (background mode)', () => {
+  test('a malicious overlayColor cannot break out of the overlay style attribute', () => {
+    const malicious = 'red" onmouseover="alert(1)';
+    const { html } = toHtml({ videoUrl: 'https://vimeo.com/123456789', isBackground: true, overlayColor: malicious }, '');
+    expect(html).not.toContain('onmouseover="alert(1)"');
+  });
+
+  test('a wrong-typed overlayOpacity (string, not number) cannot break out of the overlay style attribute', () => {
+    const malicious = '50" onmouseover="alert(1)' as any;
+    const { html } = toHtml({ videoUrl: 'https://vimeo.com/123456789', isBackground: true, overlayOpacity: malicious }, '');
+    expect(html).not.toContain('onmouseover="alert(1)"');
+  });
+
+  test('a malicious innerMaxWidth cannot break out of the inner style attribute', () => {
+    const malicious = '1200px" onmouseover="alert(1)';
+    const { html } = toHtml({ videoUrl: 'https://vimeo.com/123456789', isBackground: true, innerMaxWidth: malicious }, '');
+    expect(html).not.toContain('onmouseover="alert(1)"');
+  });
+
+  test('a malicious style.borderRadius cannot break out of the style attribute (normal mode, iframe wrapper)', () => {
+    const malicious = { borderRadius: '8px" onmouseover="alert(1)' } as any;
+    const { html } = toHtml({ videoUrl: 'https://vimeo.com/123456789', style: malicious }, '');
+    expect(html).not.toContain('onmouseover="alert(1)"');
+  });
+
+  test('a malicious style.borderRadius cannot break out of the style attribute (direct file <video>)', () => {
+    const malicious = { borderRadius: '8px" onmouseover="alert(1)' } as any;
+    const { html } = toHtml({ videoUrl: 'https://example.com/clip.mp4', style: malicious }, '');
+    expect(html).not.toContain('onmouseover="alert(1)"');
+  });
+});
+
 describe('VideoBlock.toHtml iframe src ampersand encoding (F-export review Minor)', () => {
   test('embed params joined with literal & are HTML-entity-encoded in the emitted src attribute', () => {
     // autoplay+muted+controls=false forces buildEmbedParams to concatenate