Upgrade AW and validate workflow compatibility

[aaronpowell]

Summary

Upgrade AW to the target version and ensure all impacted agentic workflows remain compatible.

Scope

• Select and apply the AW version upgrade
• Update workflow references/configuration impacted by the upgrade
• Validate all workflows in the parent scope against the upgraded version
• Document upgrade notes, compatibility considerations, and rollback guidance
• Follow the AW upgrading guide: https://github.github.com/gh-aw/guides/upgrading/

Acceptance criteria

• AW is upgraded to the agreed target version
• All workflows in epic scope pass on staged after upgrade
• Any required config or syntax changes are merged
• Upgrade and compatibility notes are documented

Parent

Part of #2076

[aaronpowell]

resolved with #2092