Prepare Stable Release v6.12.0

[github-actions]

This PR is a preview of the release that release-plan has prepared. To release you should just merge this PR 👍

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Release (2026-04-09)

• @ember/app-blueprint 6.12.0 (minor)

🚀 Enhancement

• @ember/app-blueprint
  • #243 Promote Beta and update all dependencies for 6.12 release (@mansona)
  • #144 feat: move ember-cli-build to mjs (@aklkv)

🐛 Bug Fix

• @ember/app-blueprint
  • #215 upgrade ember/optional-features to clear install deprecation warnings (@void-mAlex)
  • #119 fix: align linters with recent changes in classic app blueprint (@aklkv)
  • #208 [Bugfix release] Add globals.browser to eslint config for TS files (@mkszepp)

📝 Documentation

• @ember/app-blueprint
  • #204 Update Release.md (@mansona)

🏠 Internal

• @ember/app-blueprint
  • #247 update node for Publish CI to a version that doesn't need to update npm (@mansona)
  • #244 split tests into individual matrix jobs (@mansona)
  • #228 Enable patch publish (@mansona)
  • #211 fix release-plan alpha tag (@mansona)

Committers: 4

• Alex (@void-mAlex)
• Alexey Kulakov (@aklkv)
• Chris Manson (@mansona)
• Markus Sanin (@mkszepp)