Constant INSERT_COMPLETION_RESUMABLE_SQL 

pub const INSERT_COMPLETION_RESUMABLE_SQL: &str = r#"
    INSERT INTO ff_completion_event
        (partition_key, execution_id, outcome, occurred_at_ms, namespace, instance_tag)
    SELECT ?1, ?2, 'resumable', ?3,
           json_extract(raw_fields, '$.namespace'),
           json_extract(raw_fields, '$.tags."cairn.instance_id"')
      FROM ff_exec_core
     WHERE partition_key = ?1 AND execution_id = ?2
    UNION ALL
    SELECT ?1, ?2, 'resumable', ?3, NULL, NULL
     WHERE NOT EXISTS (
         SELECT 1 FROM ff_exec_core
          WHERE partition_key = ?1 AND execution_id = ?2
     )
"#;

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).

Binds: ?1 partition_key, ?2 execution_id (BLOB — reused for the exec_core lookup), ?3 occurred_at_ms.