Fix stale-cache proof race and consolidate release preparation

[renezander030]

What & why

The stale-cache CLI proof could observe the refreshed corpus before the detached worker released its refresh lease, producing a false CI failure. Its existing five-second poll now waits for both conditions before checking completion.

• Retain the original cache-content, stale-response, deadline, and lease-cleanup assertions.
• Document matching ATS_AGENT_ID and BEADS_ACTOR values so claimed issues are completed under the claiming worker's identity.
• Record the published 0.17.0 release date and current release features.
• Document consolidating pending consumer changes before release review and merging repository maintenance without publishing unchanged packages.

Type

• Bug fix
• Docs

Validation

• All three existing stale-cache CLI checks pass.
• npm test passes: 494 tests, lint, disclosure checks, and offline proofs.
• The worker-identity setup was verified with the published CLI against a disposable Beads database, including ownership refusal and completion by the claiming actor.
• All 13 public workspace archives have the same file contents as the verified published 0.17.0 packages. No npm release is required for this PR.

Review notes

Based on main at 2abb72a89e0a0ee3f57e7895516af15149e11177. Changes are limited to the existing stale-cache test, root README, changelog, and release guide; runtime modules, package versions, and registry manifest are unchanged.