Add an aeon skill (operate an Aeon agent instance) to the extensions registry

[aaronjmars]

Desired Behavior

There is no skill in the extensions registry for operating an Aeon instance. Aeon is an open-source framework that runs a user's own skills on a schedule in GitHub Actions; an agent working inside an Aeon repo currently has no in-registry guidance for it.

Add an aeon skill (operator playbook) in the same shape as the other integration skills here, so an agent can enable/schedule/edit skills, set the STRATEGY.md north star, and debug a skill that isn't firing, using the project's ./aeon CLI and gh.

Acceptance Criteria

• skills/aeon/ ships SKILL.md, README.md, .plugin/plugin.json, and the .claude-plugin / .codex-plugin vendor symlinks.
• The skill is registered in marketplaces/openhands-extensions.json under category integrations, with no defaultEnabled (opt-in only).
• skills/index.js and the README catalog are regenerated deterministically (node scripts/build-skills-catalog.mjs yields no further diff).
• python scripts/sync_extensions.py --check reports the extensions in sync.
• uv run --group test pytest tests/test_skills_have_readme.py tests/test_skills_catalog.py tests/test_skill_plugin_loading.py -q passes.

[github-actions]

⚠️ Not yet ready-for-dev

This issue does not yet meet the readiness criteria, so the
ready-for-dev label has not been applied (or has been removed).
The criteria are type-specific:

Bug reports (bug label):

• The ### Actual Behavior section must describe reproducible steps
  and include a command such as uv run pytest, pytest, python,
  pip, npm run, or node.
• An ### Acceptance Criteria section with at least one checklist item (- [ ] ...).

Enhancements (enhancement label):

• A ### Desired Behavior section.
• An ### Acceptance Criteria section with at least one checklist item.

What is missing:

• The issue has neither the bug nor enhancement label, so its readiness criteria cannot be evaluated. Add the appropriate label.

Edit the issue to address the gaps and the ready-for-dev label will be
applied automatically.

This is an automated readiness check posted by a workflow.

[aaronjmars]

The body already satisfies the ready-for-dev enhancement criteria (Desired Behavior + Acceptance Criteria with checklist items). Could a maintainer add the enhancement label? That will auto-grant ready-for-dev and unblock the linked PR #513.