Root cause: migrations 046-047 used explicit BEGIN/COMMIT which
conflicts with psycopg2 implicit transactions, and ALTER TABLE
on canonical_controls fails when the table doesn't exist on
production. This blocked all subsequent migrations (048-053).
Changes:
- migration_runner.py: strip BEGIN/COMMIT from SQL before executing
- 046: wrap canonical_controls ALTER in DO $$ IF EXISTS block
- 047: wrap canonical_controls ALTER in DO $$ IF EXISTS block
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>