-- =============================================
-- Education 模块 — 错题本 DDL Rollback
-- Migration: 005
-- =============================================
-- IMPORTANT: This is a documentation-only rollback.
--   No DROP/ALTER/DELETE statements are executed. The wrong_question
--   table is provenance-safe: it only accumulates data and mastering
--   is a status flag. Dropping these tables would lose student error
--   history with no recovery path.
--
-- What this migration created:
--   - education_wrong_question            (new table)
--   - education_wrong_question_idempotency (new table)
--   - education_practice_report_detail.options (new column)
--   - education_practice_session.review_fingerprint (new column)
--
-- Manual rollback requires:
--   1. Verified database backup before rollback
--   2. Operator approval (DBA sign-off)
--   3. Provenance of all wrong-question records preserved (exported)
--   4. Soft-delete via deleted = b'1' before any hard drop
--
-- These tables are NOT deleted by this script. Wrong history is
-- retained; if deletion is required by external policy, consult
-- the DBA for a verified rollback procedure.
