Derive npm dist-tag from package major in publish workflow

[vigneshwerv]

publish.yml ran a bare npm publish, which always moves the latest dist-tag to whatever version is being published.

That is wrong for maintenance releases on an older major: publishing 1.5.1 from the v1 line would point latest at it, pulling every npm install @fragment-dev/node-client back from 2.1.0 to 1.5.1.

This compares the package major against the current latest major and publishes older majors under a v<major> tag instead.

Verified against the live registry:

package version	resolved dist-tag
1.5.1	v1
2.2.0	latest
3.0.0	latest

Needed by the pending v1.5.1 backport release (branch release/v1.5.1).

[vigneshwerv]

Corrected — the original logic would have failed at the publish step.

npm rejects dist-tags that parse as SemVer ranges:

npm error Tag name must not be a valid SemVer range: v1

v1 parses as >=1.0.0 <2.0.0, and so do 1.x and v1.x. Switched to v${MAJOR}-legacy, which matches the tag 1.5.0 was actually published under.

Verified against the live registry:

version	resolved tag	npm
1.5.1	v1-legacy	accepts
1.6.0	v1-legacy	accepts
2.4.0	latest	accepts
3.0.0	latest	accepts

Context: 1.5.0 shipped from the new v1 branch (#92) and is on npm under v1-legacy, with latest still 2.3.0. That publish was run from the command line, so this workflow path is still unexercised — worth having correct before the next older-major release goes through CI.

https://claude.ai/code/session_01XAMVwbhshgNFmGj4sL18x7