Prepare Stable Release v6.9.0

[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 (2025-12-05)

• @ember/app-blueprint 6.9.0 (minor)

🚀 Enhancement

• @ember/app-blueprint
  • #152 Update all dependencies for 6.9 release (@mansona)
  • #76 Prepare 6.9-alpha (@mansona)

🐛 Bug Fix

• @ember/app-blueprint
  • #154 [bugfix beta] remove project: true from eslint config in TS projects (@mansona)
  • #78 Use strict mode for all CJS files (@simonihmig)

📝 Documentation

• @ember/app-blueprint
  • #64 Update the release document to match the ember-cli process (@mansona)
  • #81 Correct example usage command in README (@abeforgit)
  • #80 Fix formatting of README file (@bertdeblock)

Committers: 4

• Arne Bertrand (@abeforgit)
• Bert De Block (@bertdeblock)
• Chris Manson (@mansona)
• Simon Ihmig (@simonihmig)