Migrated from Method backlog

This issue was created from a legacy filesystem backlog card. GitHub Issues are now the live work tracker; repository docs remain Method evidence.

Source backlog: docs/method/backlog/v0.1.0/TEST_v0.1.0-replay-dind-proof.md
Original lane: v0.1.0
Original legend: TEST

Original backlog card

v0.1.0 Replay And DIND Proof

Status: narrow local release witness implemented; broader DIND gate remains.

Depends on:

• Durable witnessed submission persistence
• External contract proof fixture
• Contract artifact retention in echo-cas

Why now

The release sentence depends on deterministic replay. Echo must prove that the
local contract-host path can reproduce receipts, outcomes, and readings from
the retained package, submission, scheduler, and reading evidence.

Required witness

Add a local replay/DIND proof for the app contract path:

same package
+ same accepted submissions
+ same scheduler policy
+ same retained evidence
-> same receipts, outcomes, and readings

Acceptance criteria

• The external proof fixture participates in replay.
• Accepted submissions replay with stable submission identity.
• Tick receipts reproduce for the same scheduler-owned decision set.
• Reading envelopes reproduce for the same query basis, vars, aperture, and
  observer identity.
• Missing retained material produces obstruction rather than fake success.
• cargo xtask dind or a narrower documented release witness covers the
  path.

Implemented local slice

cargo xtask test-slice contract-path-release now runs the explicit local
contract path release witness: installed contract pipeline replay, reference
trusted host loop, and the serious external-consumer-shaped fixture. The command
is a narrow release witness, not a replacement for broader DIND CI gates.

Non-goals

• Do not require distributed replica import.
• Do not implement settlement shells.
• Do not require full observer-rights revelation proofs.