v0.16.28 Release linux-gnu jobs failed compile on missing
Key variants (RMenu / LWin / RWin / Apps / Sleep / Accept /
Convert / NonConvert / Junja / Kana / Separator / Browser* /
LaunchApp* / LaunchMail / LaunchMediaSelect) — all Windows-only
in enigo, but my parse_key_platform compiled them under both
Windows + Linux cfg.

Fix landed as 8974af8a19 — per-arm cfg(target_os = "windows")
on every Windows-only arm; Linux build now sees only the
variants enigo exposes there. Host build (macOS) still clean.

Since Release runs only on tag push, this bp is the first tag
that picks up the patched builtins_gui.rs.

No code changes vs. v0.16.28. 10 standard version-string bumps.