⬆️ Update MQT Templates to v1.4.2

[burgholzer]

🤖 AI text below 🤖

Description

Roll out MQT Templates v1.4.2 to the templates repository itself before updating the remaining consumers.

This PR:

• pins the templating workflow to the exact signed v1.4.2 release commit d0c5adb86d19a5095f871cb6184cfdab298e943c; and
• applies the two generated v1.4.2 AI-policy updates to the pull request template and AI usage guide.

The released v1.4.2 renderer leaves .github/release-drafter.yml unchanged, preserving the current category schema and CI & Tooling category. This supersedes #387, which was generated by v1.4.1 and would revert that migration.

Validation

• uv run --group test python -m pytest (9 passed)
• uv run prek run --all-files
• Independent render from exact release commit; both generated files are byte-identical.
• Independent verification that .github/release-drafter.yml remains byte-identical to v1.4.2.

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (if needed).
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

If PR contains AI-assisted content:

• Any agent that created, edited, or submitted GitHub content was explicitly authorized for that scope, as required by our AI Usage Guidelines.
• Every agent-authored or agent-edited public text body begins with the visible disclosure 🤖 *AI text below* 🤖 (titles are exempt).
• I have disclosed AI assistance in the PR description.
• I confirm that I have personally reviewed and understood all AI-generated content, and accept full responsibility for it.