Segments Sync Now

Enqueue an on-demand segment-sync run for the caller's org.

Every enabled, non-deleted segment in the org is re-synced against the current contact_attributes state. 202 with the arq job_id — the UI can display it for trace/debug. Per-segment advisory locks inside the runner serialise any cron tick that overlaps the manual run.

Declared above the /{segment_id} routes so a future addition of POST /{segment_id} cannot silently shadow this static path.

Note: segment membership reads from contact_attributes, which is refreshed by POST /attribute-mappings/sync-now (or the cron). If mapping config just changed, trigger attribute sync first — this endpoint does not cascade.