# Phase 6 — SQL backup integrity

Adds streaming SHA-256 checksum creation for successfully exported SQL files, a **Verify Backup…** button, and automatic checksum validation before importing when a `.sha256` sidecar is present.

The `.sha256` file must be kept alongside the `.sql` file with the same basename. The verifier reads the SQL file in 1 MiB blocks rather than loading the file into memory. Third-party SQL imports without a sidecar are allowed.

**Not yet implemented:** transaction-consistent snapshots, reliable ordering of table rows across pages, import streaming, rollback on partial restore, cryptographic signing/authenticity, or end-to-end restoration tests. A matching SHA-256 proves file integrity relative to the stored checksum, not database completeness or correctness. Do not rely on this as a production backup system.

This Linux environment cannot run Xcode; build and live-MySQL testing are required on macOS.