docs(workflows): clarify evidence-free acceptance criteria

[627150795]

Problem

Acceptance criteria without requiredEvidence can pass from the child agent's status assertion alone, while the documentation presents acceptance as an evidence ledger without explaining this distinction. This can make callers assume a description-only criterion is independently evidence-backed.

Value

Clarifies the current contract so contributors can choose between an attestation and an evidence-backed acceptance gate intentionally, without changing runtime semantics.

Approach

Document in the README and Workflow reference that a criterion without requiredEvidence is an attestation of its description, and that criteria requiring evidence-backed acceptance must declare the required evidence labels.

Validation

• node --test --experimental-strip-types tests/extensions/workflows/acceptance.test.ts — 5 passed.
• git diff --check — passed.
• Full repository check/test was not rerun for this documentation-only change; the Windows checkout currently has the previously observed CRLF format diagnostics and unrelated existing test failures.

Impact

• User-visible behavior: documentation only.
• Model-visible context/tools: none.
• Runtime/lifecycle: none.
• Persisted config/data: none.
• Compatibility/risk: no acceptance semantics changed.

Fixes #119

[627150795]

Updated this branch onto the latest upstream main. The PR remains a two-file documentation change; git diff --check and bun run lint pass. It is now mergeable and waiting for maintainer review/workflow approval.

[tt-a1i]

This focused documentation PR remains open under #277. Process it after #223 so the attestation-versus-requiredEvidence wording has one source of truth; then update to current main and run exact-head review and CI. No merge action is taken by this triage.

[tt-a1i]

Reviewed exact head 41a0ee6 against main a15a0d8. The documented attestation/evidence-backed distinction matches evaluateAcceptance: only declared requiredEvidence labels are enforced, and the existing scope criterion test confirms an accepted criterion may return an empty evidence array. Merge conflicts with #223 were resolved by preserving both the new limits/exact-match contract and this clarification. Local bun run check and bun run test passed (967 passed, 1 skipped); diff check passed.

[tt-a1i]

Reviewed exact head 25383d4 after updating onto main 2894084. The PR remains a two-file, three-line documentation clarification: criteria without requiredEvidence are attestations, while evidence-backed gates must declare labels. This matches the runtime contract and does not change behavior. Fresh required CI passed on Node 22.19.0, Node 24, and Windows; the branch is current with main. Approved for squash merge.