backstage release v2.84.0-rc.1

Added

• (chart) Add architecture and tolerations to run the pod on arm64 in #2702 by @marians

Changed

• (deps) Update node.js to v24.21.0 in #2692 by @renovate[bot]

Full Changelog: https://github.com/giantswarm/backstage/compare/v2.83.3...v2.84.0-rc.1