ci: hide nightly recovery from pull requests

[Orinks]

What changed and why

Removed the standalone Recover failed nightly CI job so pull requests no longer show an irrelevant skipped check. The unchanged recovery script now runs as a dev-push-only final step of the existing Build job after the same test and changelog gates.

What players or maintainers will notice

Maintainers will see a cleaner pull-request check list. Failed nightly recovery behavior on dev remains guarded by the existing tag, active-build, scheduled-failure, and same-day checks.

Tests and checks run

• Passed actionlint against the modified CI workflow.
• Passed 19 focused workflow and release-note tests.
• Passed repository Ruff checks.
• Passed Python byte-compilation and git diff --check.

Accessibility impact

No player-facing UI, spoken output, keyboard path, forms, headings, or live-region behavior changes. The Accessibility Agents lead and required specialists passed the exact diff; removing the skipped check reduces screen-reader navigation noise in GitHub's checks list.

Changelog

• This change is not player-facing. The commit includes changelog: none, which is accepted by the repository changelog gate.