isolating-product-facade-contracts

Start with hogli product:isolate:scan to map cross-boundary references, then define frozen pydantic dataclasses in facade/contracts.py, build a thin facade/api.py, migrate callers in one pass, and move presentation to consume the facade. Finish by enabling tach interfaces and the backend:contract-check script.

Run hogli product:maturity and product:isolate:scan. A fresh product has no facade directory, a mid-sweep product has contracts and api but core still imports internals, and a mid presentation-wave product still has ignore_imports TODO entries in pyproject.toml.

Only after the product is fully isolated: no ignore_imports entries remain, presentation is thin, and the tach boundary is on. hogli product:lint blocks the script while deferred entries exist because the skip is unsound until then.

Yes. Cross-cutting tests exercise a product's HTTP API in-process by URL with zero imports, which import-graph tools cannot see. The facade seals presentation so every observable behavior lives behind the boundary, making the CI skip sound.

Seal the relation with related_name="+" and remove any explicit related_query_name, then delete its line from products/model_crossing_uses_baseline.txt. Give callers that need reverse access a facade read function instead.

The scan only walks backend.* imports, so it misses reverse accessors, string-based signal senders, test-infrastructure imports, product-root surfaces like dags/, HogQL system tables, and dotted-string config. Use git grep "products.<name>" and the scan's string-reference section to find them.