feat: add BLIF Flow v2 persistence scaffolding

migrations/011_blif_flow_v2_persistence_down.sql

@@ -0,0 +1,12 @@
+-- Reversible rollback for BLIF Flow v2 persistence scaffolding.
+
+DROP TABLE IF EXISTS opportunity_flow_transitions;
+
+DROP INDEX IF EXISTS ix_tasks_superseded_by_task_id;
+DROP INDEX IF EXISTS ix_tasks_resolved_by_event_id;
+ALTER TABLE tasks DROP COLUMN IF EXISTS superseded_by_task_id;
+ALTER TABLE tasks DROP COLUMN IF EXISTS resolved_by_event_id;
+ALTER TABLE tasks DROP COLUMN IF EXISTS resolved_at;
+ALTER TABLE tasks DROP COLUMN IF EXISTS resolution_code;
+
+DROP TABLE IF EXISTS opportunity_flow_state_v2;