Signed-off-by: moderation <michael@sooper.org>

Replace removed std.fs.File/deprecatedWriter with std.Io.File.stdout()
and std.process.Init-based main. Replace std.Thread.sleep with io.sleep.
Fix sleep duration from 16us to 16ms for proper ~60fps timing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cube file