Update node, don't install npm explicitly

[simolus3]

This applies #1037 to the main branch. Original PR description:

This is an attempt to fix the broken v1 release:

• npm install -g npm@latest didn't work with node 24.12 since it's too old.
• and since node now ships with an npm cli version capable of trusted publishing, we don't actually need to install npm explicitly anymore.

If this works, I'll also apply it to the main branch which likely has the same issue.

[changeset-bot]

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Latest commit: f7301a9

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