add Faq section schema

apps/sanity/schema/Components.ts

@@ -1,12 +1,14 @@
 import { defineType } from "sanity";
 import SimpleCtaSection from "./components/SimpleCtaSection";
+import Faq from "./components/Faq";
 
 export default defineType({
   name: 'components',
   type: 'array',
   title: 'Components',
   of: [
     SimpleCtaSection,
+    Faq,
   ],
   options: {
     insertMenu: {

apps/sanity/schema/components/Faq.ts

@@ -0,0 +1,57 @@
+import { defineField } from 'sanity';
+import sectionId from '../ui/sectionId';
+import { toPlainText } from '../../utils/to-plain-text';
+
+const name = 'Faq';
+const title = 'FAQ';
+const icon = () => '❓';
+
+export default defineField({
+  name,
+  type: 'object',
+  title,
+  icon,
+  fields: [
+    defineField({
+      name: 'heading',
+      type: 'Heading',
+      title: 'Heading',
+      validation: Rule => Rule.required(),
+    }),
+    defineField({
+      name: 'list',
+      type: 'array',
+      of: [
+        defineField({
+          name: 'item',
+          type: 'reference',
+          to: [{ type: 'Faq_Collection' }],
+          options: {
+            filter: ({ parent }) => {
+              const selectedIds = (parent as { _ref?: string }[])?.filter(item => item._ref).map(item => item._ref) || [];
+              if (selectedIds.length > 0) {
+                return {
+                  filter: '!(_id in $selectedIds)',
+                  params: { selectedIds }
+                }
+              }
+              return {}
+            }
+          }
+        }),
+      ],
+      title: 'List',
+      validation: Rule => Rule.required().unique(),
+    }),
+    ...sectionId,
+  ],
+  preview: {
+    select: {
+      heading: 'heading',
+    },
+    prepare: ({ heading }) => ({
+      title: title,
+      subtitle: toPlainText(heading),
+    }),
+  },
+});