launch-payload-render-parity

Summary

This is a REMAINDER spec. A review on 2026-09-20 against the v0.9.0 tree found the intent about half delivered; the product thinker ruled that the delivered half is recorded on the intent (its ## Delivery Status section) and this spec scopes only what is still open.

Scope

Two pieces:

1. File-level parity diff. The rendered payload is compared with the previous release's payload (the tag the cut derives from): every path added, changed or removed is listed with its digest, in the preview and in the cut's receipt. With no previous tag every path is reported as added and the report says why; a baseline that cannot be read is a named refusal, not an empty diff. Today only a record-level diff exists (release/emit.go, added and removed surfaces), never files.
2. Deep smoke tier. For every command page and skill in the rendered payload, the tier renders its help and frontmatter in an isolated subprocess rooted at the rendered tree, so a page that resolves on disk but fails to load is caught before the tag. The original criterion's Python-import clause is moot (nothing shipped imports) and is recorded as such on the intent.

Out of scope

The render itself, the structural exclusion of the record namespace, the symlink defence and the no-residue guarantee are delivered and cited on the intent.

Approach

The parity diff reads the previous payload from the tag's release asset when present and from a fresh render at that tag otherwise, so it never needs a stored baseline file (adr-31 keeps the version derived, so there is no baseline to seed). The deep tier is a second level of internal/core/launch/ smoke.go, opt-in by flag in the preview and always-on in the cut.