security: bump mysql to 8.0.46-debian (8.0.38 → latest 8.0.x patch) (#839)

Pulls in the accumulated 8.0.x patch updates since 8.0.38 (released 2024-07). 8.0.46 is the most recent debian-tagged release on the official mysql image at the time of writing. Upgrade path verified locally for existing 8.0.38 deployments: - `docker compose pull && docker compose up -d` recreates only the copilot-mysql container and reuses the mysql-data named volume. - MySQL runs the data-dictionary upgrade itself on first boot ("Server upgrade from '80038' to '80046' completed") — no manual `mysql_upgrade` step required. - alembic_version, table count, and seed data (connectors, roles, integrations, users) are byte-identical pre/post. - Backend container stays up; SQLAlchemy/aiomysql pool reconnects automatically. APScheduler logs a single transient "Lost connection to MySQL server during query" during the few seconds of MySQL downtime, then recovers. Total downtime in the test: ~5s end-to-end. Co-authored-by: taylor_socfortress <taylor.walton@socfortress.co> Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>