Rewrites our own comments, help text, and example READMEs that named
Railway or linked railway.app so they describe what they do instead.
Retargets the changelog generator and RELEASE.md's Actions/release
links at this repo. Leaves upstream issue links, the MIT copyright,
and the builder/runtime/frontend image references untouched -- those
still point at ghcr.io/railwayapp because we don't publish our own
copies of those images yet.
Co-authored-by: Hanzo Dev <[email protected]>