Retrieve Typeform form responses via the Responses API with cursor pagination and filters

Documented steps

1. Auth: Authorization: Bearer {token} with responses:read scope; EU accounts must use their regional base URL.
2. GET https://api.typeform.com/forms/{form_id}/responses -H 'Authorization: Bearer {token}'
3. Pagination: `page_size` (cap 1000) plus exclusive cursor params `before`/`after` — there is no page-number parameter; for >1000 responses page with since/until or before/after.
4. Date filters: `since` and `until` accept Unix timestamps or ISO 8601 (e.g. 2020-03-20T14:00:59).
5. Completion filter: `response_type` = partial | completed | started (comma-separable); the older boolean `completed` param is DEPRECATED.
6. Sorting: `sort` defaults differ by state — submitted_at,desc for completed, staged_at,desc for partial, landed_at,desc for started; response_type also changes which timestamp since/until filter on.
7. Narrow further with included_response_ids / excluded_response_ids, `query` (text search over answers/hidden/variables), `fields`, and `answered_fields`.
8. Read total_items and page_count from the body to know when to stop; iterate items[].
9. Official docs: https://www.typeform.com/developers/responses/reference/retrieve-responses/ ; https://www.typeform.com/developers/get-started/responses-data-center/