Upstream release:
https://github.com/mbadolato/iTerm2-Color-Schemes/releases/tag/release-20251006-150522-c07f0e8

Co-authored-by: mitchellh <1299+mitchellh@users.noreply.github.com>

Release notes at:
 https://github.com/vancluever/z2d/blob/v0.9.0/CHANGELOG.md

This release brings our Zig 0.15.x branch into main, now that Ghostty is
on it too.

Additionally, this adds major speedups to the default path (filling with a
solid color using the default operator).

This adds a new script we can manually run that downloads all the files
that need to be uploaded to the mirror and updates our build.zig.zon.
The upload still happens manually [by me] but this simplifies the task
greatly.

Since we now use uucode, we don't need ziglyph anymore. Ziglyph was kept
around as a test-only dep so we can verify matching but this is
complicating our Zig 0.15 upgrade because ziglyph doesn't support Zig
0.15. Let's just drop it.