Bug: PR creation produced literal \n in body (template not applied)

## Summary
PR #1310 initially showed literal `\n` characters in the body, indicating the PR body was passed incorrectly (string with escapes) rather than true newlines, and not reliably following `.github/PULL_REQUEST_TEMPLATE.md`.

## Expected
- PR body renders with proper markdown newlines
- PR content follows `.github/PULL_REQUEST_TEMPLATE.md` sections

## Actual
- Literal `\n` characters appeared in the PR body
- Template sections were not consistently applied

## Suspected Cause
- `gh pr create` invocation passing body as a single quoted string; needs `--body-file` or API usage that supplies real newlines

## Acceptance Criteria
- Update PR creation path(s) to avoid escaped newlines
- Ensure `.github/PULL_REQUEST_TEMPLATE.md` is used or mirrored when auto-creating PRs
- Add quick smoke test/recipe for local validation

## References
- PR #1310
- `.github/PULL_REQUEST_TEMPLATE.md`

Start by locating the PR creation path that invokes `gh pr create`, then inspect `.github/PULL_REQUEST_TEMPLATE.md` and PR #1310 for the observed behavior. Validate that generated bodies render real markdown newlines and use the template sections, then add the requested quick smoke test or local validation recipe.

Written by the indexing model from the issue text.