Add Node devcontainer with firebase tools.

[aebrahim]

This makes it easier to run the demo without installing dependencies.

Tested with

firebase login
npm run demo

[google-cla]

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[aebrahim]

@googlebot I fixed it.

[dineshmaxi]

Never mind my comment

[dackers86]

Thank you for taking the time to submit this feature request.

This is a great idea and definitely something we can consider for the future. It is not currently prioritised for our immediate new version roadmap, as we are focusing on a new upcoming release.

In the meantime, we will keep this issue open so we can revisit it during a later planning cycle, particularly as we gather more feedback from the community.