fix: add sanity-check mock content-type.js for unit tests

Unit tests (test/unit/mock/objects.js) import singlepageCT from
../../sanity-check/mock/content-type. Add content-type.js so
test:unit:report:json runs and report.json is generated in CI.

Author: AniketDev7

test/sanity-check/mock/content-type.js

@@ -0,0 +1,34 @@
+/**
+ * Content type mock for unit tests (singlepageCT).
+ * Mirrors test/typescript/mock/contentType.ts for test/unit/mock/objects.js.
+ */
+export const singlepageCT = {
+  content_type: {
+    options: {
+      is_page: true,
+      singleton: true,
+      title: 'title',
+      sub_title: []
+    },
+    title: 'Single Page',
+    uid: 'single_page',
+    schema: [
+      {
+        display_name: 'Title',
+        uid: 'title',
+        data_type: 'text',
+        mandatory: true,
+        unique: true,
+        field_metadata: { _default: true }
+      },
+      {
+        display_name: 'URL',
+        uid: 'url',
+        data_type: 'text',
+        mandatory: true,
+        field_metadata: { _default: true, instruction: '' }
+      }
+    ]
+  },
+  prevcreate: true
+}