Create a survey template from a SurveyJS schema.

The survey field is a raw SurveyJS survey model (JSON). It is validated
against the Edusign scope, then canonicalized through the SurveyJS library and stored — so a
template created here behaves exactly like one built in the Edusign survey editor.

survey structure

• title (required, ≤ 200), description (optional, ≤ 2000)
• pages: array of { title?, description?, elements: [...] } — at least one page, and at least
  one element per page
• each element (question): { "type": ..., "title": ..., "isRequired"?: boolean, "choices"?: [...] }.
  You do NOT need to set name on pages/questions — they are auto-generated (page1…, question1…).

Supported question types: radiogroup, checkbox, dropdown, tagbox, boolean, rating,
ranking, text, comment. Choice types (radiogroup, checkbox, dropdown, tagbox, ranking)
require a non-empty choices array.

Choices follow SurveyJS: { "value": "...", "text": "..." } (a plain string also works). text
is shown to the respondent, value is what gets stored in the answer. Tip: set value = text to
match a template where the labels were simply typed in the editor.

Rejected (422): unsupported types (matrix, file, imagepicker, …); quiz mode
(showCorrectAnswers, correctAnswer); conditional logic (visibleIf, enableIf, triggers).
logo and timer properties are ignored.

Anonymity is set via the top-level anonymous flag — not inside survey.

📖 SurveyJS references: Create a simple survey
· Question types & properties.