Establishes the local pre-push gate. preflight.sh runs four blocks: version
consistency, manifest shape (Icon plus all ImageUrls), changelog sync, plus a
release build as compile-health smoke. setup-hooks.sh wires core.hooksPath to
.githooks. .gitignore opens scripts/ for tracking (setup-dev-env.sh stays
private). Test execution itself lives in a separate local repository and is
not part of this codebase.
