feat(skills): add read-only Agent Guild trust check

[AgentTanuki]

• A human has tested these changes.

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Why

OpenHands agents increasingly delegate to other autonomous agents and external services. This adds a narrow, evidence-backed pre-delegation check without granting payment or mutation authority.

Summary

• Add a progressive-disclosure agent-guild-trust skill for autonomous-agent vetting and passport verification.
• Treat all remote response fields as untrusted data and forbid automatic delegation, payment, registration, dependency installation, and other side effects.
• Add the marketplace entry, generated catalog artifact, vendor manifests, and human-facing README.

Issue Number

N/A - new marketplace skill.

How to Test

Run:

python scripts/sync_extensions.py --check
pytest tests/test_skill_plugin_loading.py::TestAllMarketplaceSkillsHaveManifests -q
pytest tests/test_sync_extensions.py -q
pytest tests/test_skills_catalog.py -q
git diff --check

Observed locally: 4, 34, and 37 tests passed respectively. The sync check reported only the repository's pre-existing non-blocking issue-duplicate-checker coverage warning.

Video/Screenshots

Not applicable; this is a Markdown skill and generated catalog update.

Notes

The skill uses the host's existing HTTP or MCP client. It does not install or execute remote code, and a trust verdict is explicitly evidence rather than authority.

[all-hands-bot]

👋 This PR needs a couple of things fixed before OpenHands can review it:

• the PR description's HUMAN: section needs at least 20 characters describing what you tested, not just the template placeholder

Push an update once this is addressed and this check re-runs automatically.

This is an automated check - no AI was used to generate this comment.