-- TASK_2 prerequisite repair: local optimistic generation (NOT FC answer_revision).
-- Existing TASK_2 installations only. Run once, before deploying the new entity.
-- For a fresh schema use fc_projection_and_apply_intent.sql; do not run both.
-- MySQL 5.7; non-idempotent: inspect SHOW COLUMNS before execution.
ALTER TABLE fc_answer_projection
    ADD COLUMN projection_version BIGINT NOT NULL DEFAULT 0
    COMMENT 'Local optimistic generation; guards MQ/receipt/authoritative repair writes';