fix(builder): deterministic ids for NumberCounter + form-relay marker

Two components of the det-id bug class were missed in the earlier migration:
NumberCounter's wrapper/counter ids and count-up script, and the shared
form-relay-wiring fid (used by ContactForm/FormContainer). Both used
Math.random() for exported HTML ids, breaking caching/diffing across exports.

Migrate both to scopeId(nodeId, fallbackSeed, prefix), threading nodeId
through NumberCounter.toHtml and relayFormWiring (via ContactForm.toHtml and
FormContainer.toHtml, both now passing nodeId as their 3rd arg).

craft/src/components/forms/ContactForm.tsx

@@ -167,7 +167,7 @@ ContactForm.craft = {
 
 /* ---------- HTML export ---------- */
 
-(ContactForm as any).toHtml = (props: ContactFormProps, _childrenHtml: string) => {
+(ContactForm as any).toHtml = (props: ContactFormProps, _childrenHtml: string, nodeId?: string) => {
   const formStyle = cssPropsToString({
     padding: '32px',
     display: 'flex',
@@ -212,7 +212,7 @@ ContactForm.craft = {
     alignSelf: 'flex-start',
   });
 
-  const { marker, actionAttr, honeypot } = relayFormWiring(props.recipientEmail, props.thankYouUrl, props.formAction);
+  const { marker, actionAttr, honeypot } = relayFormWiring(props.recipientEmail, props.thankYouUrl, props.formAction, nodeId);
 
   // The form-sender relay delivers success via a full-page 303 redirect
   // (to thankYouUrl or a hosted thanks.php page) -- there is no in-page JS