Fix errors/warnings for pre-existing code smells after reintroducing editorconfig et al - #393

Canceling since a higher priority waiting request for ubuntu-latest-refs/pull/393/merge exists

The operation was canceled.

Canceling since a higher priority waiting request for ubuntu-latest-refs/pull/393/merge exists

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