Add Node.js v24 and update default variant to use it

[dslatkin]

Added v24 variants since it's supported in both images now:

• https://mcr.microsoft.com/v2/devcontainers/javascript-node/tags/list
• https://mcr.microsoft.com/v2/devcontainers/typescript-node/tags/list

Omitting Trixie (Debian 13) variant since it's currently experimental.

Also updated default to Node 24 which is supported in both Azure functions and Azure web apps now.

Closes #385

[awsr]

Seconding this. I was really surprised at how far behind the node dev container template is. Even the official Node.js site shows using a 24-alpine container by default instead of just having the download as the main way to use it.

[dslatkin]

Seconding this. I was really surprised at how far behind the node dev container template is. Even the official Node.js site shows using a 24-alpine container by default instead of just having the download as the main way to use it.

Just made #385 as an issue to track as well