chore: require clean working tree in pre-push hook

scripts/git-hooks/pre-push

@@ -4,6 +4,13 @@ set -euo pipefail
 repo_root="$(git rev-parse --show-toplevel)"
 cd "$repo_root"
 
+echo "pre-push: checking for a clean working tree"
+if [[ -n "$(git status --porcelain)" ]]; then
+	echo "pre-push: refuse to push — working tree is not clean. Commit, stash, or remove changes first:" >&2
+	git status --short >&2
+	exit 1
+fi
+
 gdlint_bin=""
 gdformat_bin=""