Sync ag-shared Subrepo Across AG Repos

Orchestrate syncing external/ag-shared/ changes from the current repo to all other AG repos that consume the subrepo. This handles the full yarn subrepo push / pull cycle, companion changes, and cross-linked PRs.

Help

If the user provides a command option of help:

• Explain how to use this skill.
• Explain the prerequisites and what will happen.
• DO NOT proceed, exit the skill immediately after these steps.

Prerequisites

• Git CLI, GitHub CLI (gh), and yarn must be available.
• git subrepo must be installed (git subrepo --version).
• Use yarn subrepo for push and pull (never raw git subrepo push/pull). The wrapper handles edge cases like stale parent references. Other subrepo commands (e.g. git subrepo status, git subrepo clean) use git subrepo directly.
• Never edit external/ag-shared/.gitrepo manually. Only subrepo commands should modify this file.
• Should be on a feature branch. If on latest/main/master, the skill will offer to create one.