[ACT-05] Verify one cross-surface ecosystem changelog

[EmersonBraun]

Goal

Compare one real change across the AgentsKit, Registry, Playbook, and AKOS surfaces. Use the agent to draft a changelog, then verify dates, canonical links, audience, and source repositories manually.

Evidence

• Human guide: docs/agents/ecosystem-changelog-ecosystem.md
• Agent test: registry/ecosystem-changelog-ecosystem/agent.test.ts

Acceptance criteria

• Every statement has a source and date.
• Canonical ownership is clear for each surface.
• The final changelog is labeled as human-reviewed.
• Stale or conflicting source information is documented.

Human gate

An ecosystem maintainer must verify the final changelog before any release communication.