Module signal 

SQL statements for signal delivery ops (RFC-023 Phase 2b.2.1).

Mirrors ff-backend-postgres/src/signal_event.rs + the signal-delivery bodies in suspend_ops.rs.

Constants

INSERT_COMPLETION_RESUMABLE_SQL

Completion outbox insert for the resumable transition when a signal satisfies a waitpoint. Back-fills namespace + instance_tag from ff_exec_core.raw_fields via a co-transactional SELECT so tag-filtered subscribers receive the event (Phase 3.2 fix — pre-fix both columns landed NULL). flow_id stays NULL here (matches the PG minimal insert shape at ff-backend-postgres/src/suspend_ops.rs:845-854).

INSERT_SIGNAL_EVENT_SQL

Append one signal-delivery event to the outbox.