[EPIC E0] Delivery Safety and Integration Harness

## Outcome

ten contributors can merge small changes without relying on maintainer memory or treating compilation as product evidence.

## Delivery contract

- **Epic:** E0
- **Priority:** P0
- **Wave:** Wave 0 - Safe integration
- **Milestone:** Mid-term - Governed Vertical Slice
- **Area:** area:delivery

## Completion evidence

E0-T1–T5 are reproducible by a teammate; E0-T6 is active once the real-backend slice exists. E0 is not complete merely because a workflow YAML file exists.

## Child delivery

Implementation tickets are attached as native GitHub sub-issues. Closing child PRs is not sufficient: this Epic closes only when the completion evidence above is reproducible.

## Product constraints

- Preserve the claim-scoped, backend-neutral architecture contract.
- Do not broaden this Epic into deferred platform work.
- Gate failures must narrow scope or repair the harness before more implementation is added.

Begin with the native GitHub sub-issues for E0-T1–T6 and compare their requirements with the Delivery contract and Completion evidence above. Reproduce the listed evidence as a teammate would; E0 is done only when E0-T1–T5 are reproducible and E0-T6 is active once the real-backend slice exists, rather than when workflow YAML merely exists.

Written by the indexing model from the issue text.