Manually reverse the watcher's auto-suppression decision.

Flips do_not_contact back to false + clears declined_at, decline_reason, decline_class. Use sparingly — this is the operator's explicit override when an auto-suppress was wrong (e.g. a publisher said "remove me from this list" meaning "remove from THIS cohort, send me the right one" rather than a hard out).

The reason is logged for audit (server log only — not persisted on the row, intentionally, so the next auto-suppress can stamp fresh without the operator manually clearing audit text).