Inspect sample outputs

Every file below is checked-in fixture/sample output, not current DataHub evidence. The official scenario version is 2026-08-04.1.

• Compatibility SQL sample — artifact schema migration-artifact/1.0.0, validated by artifact tests.
• Validation receipt sample — fixture result tied to the same compatibility artifact.
• Day 2 simulation receipt — simulation schema 1.0.0, scenario 2026-08-04.1.

Use Receipts and manifests for field semantics and Migration artifact contract for what the fixture does and does not prove.