* Remove "Confirm Root Account Name" step that referenced non-existent star icon
* Add detailed instructions for updating static account map in _defaults.yaml
* Clarify that root_account_account_name should always be core-root internally
* Move root account verification guidance to account ID update step with current AWS console labels

Addresses customer feedback about outdated UI references in account setup documentation.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

The REPO_ACCESS_TOKEN PAT was hitting GitHub API rate limits, causing
release asset downloads to fail with HTTP 403 errors. The GITHUB_TOKEN
has separate per-workflow rate limits that won't be exhausted by other
workflows.

Use github.token directly in the composite action instead of the PAT.
This works because composite actions have access to the github context.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>