chore: remove Corepack usage from Dockerfiles and add CI build

[Mattral]

Replaces Corepack installs with direct pnpm installs in Dockerfiles and adds a GitHub Actions workflow to build the affected images as a smoke test.

related issue

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[mergify]

❌ The current Mergify configuration is invalid

Details

• Extra inputs are not permitted @ root → pull_request_rules → item 0 → actions → merge → strict
• Extra inputs are not permitted @ root → pull_request_rules → item 0 → actions → merge → commit_message → title+body

[bestickley]

Thanks for your contribution @Mattral! I see you're assuming pnpm, what if user is using npm or yarn as package manager?

[Mattral]

Thanks for your contribution @Mattral! I see you're assuming pnpm, what if user is using npm or yarn as package manager?

Thank you for the feedback! You’re right, the current changes assume pnpm as the package manager. To make this more flexible, I’ll update the Dockerfiles and CI scripts to detect and use the user’s preferred package manager (npm, yarn, or pnpm). I’ll add logic to check for a lockfile (package-lock.json, yarn.lock, or pnpm-lock.yaml) and use the corresponding tool. I’ll also update the documentation to clarify this behavior.

[mergify]

❌ The current Mergify configuration is invalid

Details

• Extra inputs are not permitted @ root → pull_request_rules → item 0 → actions → merge → strict
• Extra inputs are not permitted @ root → pull_request_rules → item 0 → actions → merge → commit_message → title+body

[Mattral]

This update adds support for all major Node.js package managers (npm, yarn, pnpm) in Dockerfiles and CI workflows. The build system now automatically detects the correct package manager based on the presence of a lockfile (yarn.lock, package-lock.json, or pnpm-lock.yaml) and uses the appropriate install/run commands. Documentation has been updated to explain the new detection logic.

[Mattral]

May I ask for a review on what could be improved?

[bestickley]

Hey @Mattral, I should have mentioned this initially, but I think #187 removes the need for this. Do you agree?

[Mattral]

Hey @Mattral, I should have mentioned this initially, but I think #187 removes the need for this. Do you agree?

Oh I can see it. Thank you for following up.

[bestickley]

You're welcome! Still really appreciate you pushing cdk-nextjs forward :) I'll close the related issue.