Implement existing API types

frontend-reactive/app/models/custom-account-field.ts

@@ -0,0 +1,10 @@
+import Model, { attr } from '@ember-data/model'
+
+export default class CustomAccountFieldModel extends Model {
+  @attr declare createdAt: Date
+  @attr declare updatedAt: Date
+  @attr declare key: string
+  @attr declare value: string
+  @attr declare verified?: boolean
+  @attr declare belongsToId: string
+}