Add author-primary review-nudge/reviewer-ping triage templates

[choo121600]

why

The project-specific pr-management-triage template library was
missing the author-primary variants of review-nudge and
reviewer-ping, as well as the request-author-confirmation
template.

As a result, some triage flows fell back to reviewer-targeted
templates even when the author should have been the primary recipient,
creating unnecessary reviewer pings and confusion about the PR state.

Change

This PR adds:

• review-nudge (author-primary)
• reviewer-ping (author-primary)
• request-author-confirmation

to .apache-steward-overrides/pr-management-triage-comment-templates.md.

The request-author-confirmation template also includes the required
ready for maintainer review confirmation marker string used by the
framework precondition.

TOC regenerated. No framework or skill changes; adopter-local override
only.

---

Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)
  claude opus 4.7

---

• Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
• When adding dependency, check compliance with the ASF 3rd Party License Policy.
• For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

[23tae]

LGTM 👍