Resume & partials

When a respondent starts a survey we drop a cookie that points at their in-flight buffer. As long as the cookie is intact and the buffer hasn't been swept by retention, they pick up exactly where they left off.

For cross-device resume, generate a signed resume URL (route name surveys.resume) and email it to the respondent. The URL drops the cookie when visited and redirects to the survey landing.

Retention

Abandoned buffers — buffers without a completed_submission_id — are pruned by the daily retention sweep using each team's plan retention window. Completed responses are pinned to the lifetime of the materialized submission and follow the same rules as any other submission row.