make sure update checks are skipped if on a tag instead of a branch.

linux-game-manager.sh

@@ -290,6 +290,10 @@ check_update() {
     if ! [[ -d ".git" ]]; then
         return
     fi
+    # Check if we're in a detached HEAD state
+    if ! git symbolic-ref -q HEAD &> /dev/null; then
+        return
+    fi
     local url
     url="$(git ls-remote --get-url)"
     if [[ "$url" =~ ^ssh://|git@|gitea@ ]] || [[ -z "$url" ]]; then