Teach Agora agents to document public contract changes

[kelos-bot]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Adds one shared Agora agent instruction requiring matching README, example, or skill documentation whenever an implementation changes a public contract.

This is motivated by Agora PR #7, where a generated implementation changed the required AGORA_URL behavior but initially omitted the corresponding README and skills/agora-reporting updates. The review finding identified the missing public-contract documentation as P2, and the responder follow-up confirmed that both documentation surfaces needed updates.

The August 12–19 review window contained no Agora PRs, so the audit also covered the repository's full recent set (#1, #2, #3, #6, and #7). Only #7 had substantive review feedback, and no other configuration rules were added.

Which issue(s) this PR is related to:

N/A

Special notes for your reviewer:

The shared rule lives in self-development/agora/agentconfig.yaml so all Agora implementation agents receive it. Existing planner and reviewer prompts already check documentation completeness; this closes the corresponding gap in the shared implementation behavior without duplicating skills.

Validation: make verify

Does this PR introduce a user-facing change?

NONE

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Summary by cubic

Adds a shared rule that requires documentation updates in the same PR when an Agora public contract changes. Previously, contract changes could land without synchronized docs; now agents must update the matching README.md, examples/, or skills/ docs to prevent drift.

Review and rollout

• Rule location: self-development/agora/agentconfig.yaml; applies to all Agora implementation agents.
• Affects environment variables, Kubernetes manifests, and the installable skills/agora-reporting contract.
• No runtime behavior change; no migrations.
• Reviewers should expect doc updates alongside any contract change.
• Validate with: make verify.

^{Written for commit db7d5b6. Summary will update on new commits.}