fix(vermeer): handle Louvain degenerate inputs safely - #373

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-java@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

The 'adopt' legacy AdoptOpenJDK distribution is deprecated and will be removed in setup-java v6. Please migrate to the 'temurin' distribution.

setup-java v4 is deprecated and will no longer receive updates. Please migrate to actions/setup-java@v5.

Restore cache failed: Some specified paths were not resolved, unable to cache dependencies.