Replace the git clone/fetch pipeline with a curl + miniz HTTPS
ZIP download. The engine streams one archive, extracts only the
catalog roots, and reuses flatten to install flat files, so the
libgit2 submodule and its build integration are gone.
Drop the pre-download reachability probe and the commit-SHA
parser; reachability is implied by the download itself and the
SHA only fed the old git flow. Mirror selection stays in
CheatMirrorFactory (auto: cnb.cool for zh-Hans, GitHub otherwise;
explicit github/cnb skips fallback).
curl verifies peer+host against the embedded CA bundle and now
distinguishes certificate time-skew from other verification
failures, surfacing a dedicated clock notification. Revert the
util CMake target back to "util" now that libgit2 no longer
claims that name.
Expose catalog download on the Game Tools page and put the
mirror picker in Preferences. Probe gstatic/miui generate_204
before clone so auto can pick GitHub or cnb.cool by reachability.
Also fix the CNB slug, rename the util CMake target so it no
longer clashes with libgit2, and keep last-error text off the
download button.
Bring back DOWNLOAD_CHEATS as a background git clone/fetch of
cheat catalogs, then reuse flatten to install flat files.
Catalog identity and GitHub/cnb.cool mirrors stay in separate
modules so a new source does not rewrite the download pipeline.
auto mirror uses cnb.cool for zh-Hans and GitHub otherwise;
explicit github/cnb skips fallback. libgit2 is an optional
submodule (v1.8.4); without it the client stays a stub.
Hexwell