Remove trailing whitespace from lines

[koitsu]

No description provided.

[familiarcow]

Thanks @koitsu — re-applied this against current main in #26 (the original PR was based on 5813e8d which is several commits behind, and most of the touched files have since moved with PR #21, the Liquify failover work, and the PR #24 take-over). Same files, same intent, full attribution preserved via Co-authored-by.

I also added .editorconfig with trim_trailing_whitespace = true so this won't regress.

Closing in favor of #26.