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/MapEmbed.tsx

@@ -12,7 +12,15 @@ interface MapEmbedProps {
 
 function buildMapUrl(address: string, zoom: number): string {
   const encoded = encodeURIComponent(address);
-  return `https://maps.google.com/maps?q=${encoded}&z=${zoom}&output=embed`;
+  // `zoom` is declared as `number` but is not runtime-type-checked (AI
+  // update_props / deserialized state can hand us anything). The final src
+  // string is still run through escapeAttr(safeUrl(...)) at the toHtml call
+  // site, which already blocks attribute-breakout -- but Number-coercing
+  // here too keeps the emitted URL a well-formed `z=<digits>` query param
+  // instead of smuggling arbitrary attacker text into it.
+  const z = Number(zoom);
+  const safeZoom = Number.isFinite(z) ? z : 14;
+  return `https://maps.google.com/maps?q=${encoded}&z=${safeZoom}&output=embed`;
 }
 
 export const MapEmbed: UserComponent<MapEmbedProps> = ({