`gh aw add` rejects a direct workflow file path with a branch ref

[arthurfvives]

Summary

gh aw add rejects a direct workflow file path with a branch ref:

gh aw add MY-ORG-NAME/my-repo-name/agentic-workflows/pr-review.md@feature/github-agentic-workflows

It fails with:

✗ invalid specification 'MY-ORG-NAME/my-repo-name/agentic-workflows/pr-review.md@feature/github-agentic-workflows': not a valid workflow path or repository package
  repository must be in format 'owner/repo'. Example: github/gh-aw

Expected behavior

Either:

1. gh aw add owner/repo/path/to/workflow.md@ref should work; or
2. the docs should clarify that gh aw add only accepts repository packages / workflow IDs, and that direct workflow file paths require a full GitHub URL.

Context

Repo: MY-ORG-NAME/my-repo-name
Branch: feature/github-agentic-workflows
Workflow path: agentic-workflows/pr-review.md

This shorthand with blob also fails, which makes sense because it is not a full URL:

gh aw add MY-ORG-NAME/my-repo-name/blob/feature/github-agentic-workflows/agentic-workflows/pr-review.md

Error:

✗ invalid specification 'MY-ORG-NAME/my-repo-name/blob/feature/github-agentic-workflows/agentic-workflows/pr-review.md': not a valid workflow path or repository package
  repository must be in format 'owner/repo'. Example: github/gh-aw

Question

Is direct owner/repo/path/to/workflow.md@branch intended to be supported by gh aw add, or is that format only intended for source, imports, and update?

[pelikhan]

@copilot #1: gh aw should support these specs.