Goal
Add an automated guard that rejects product-code imports of the full-snapshot fixture.
Acceptance criteria
- Product paths fail CI if they import full-snapshot fixture modules.
- Fixture imports remain allowed in specs, tests, and explicitly named migration/import tools.
- The guard catches stale adapter names and aliases as well as the current fixture name.
Goal
Add an automated guard that rejects product-code imports of the full-snapshot fixture.
Acceptance criteria