Fix carry-over on Pages: add 404.html and tolerate 200-with-HTML

Pages serves index.html with 200 for unknown paths when there is no
404.html, so a never-published channel looked published and jq failed on
the HTML. Add a real 404 page and treat a 200 without a latest.json as
absent.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01JdMNbY5hLR7FjtfEE712xG

.github/scripts/stage-pages-site.sh

@@ -17,7 +17,7 @@ case "$channel" in prod) other=dev ;; dev) other=prod ;; *) echo "bad channel: $
 
 rm -rf "$out"
 mkdir -p "$out/$channel" "$out/$other"
-cp site/index.html site/_headers "$out/"
+cp site/index.html site/404.html site/_headers "$out/"
 
 name="$(basename "$apk")"
 cp "$apk" "$out/$channel/$name"
@@ -47,6 +47,11 @@ fi
 if [ "$code" = 404 ]; then
   echo "No $other channel published yet; skipping."
   rm -rf "$out/$other"
+elif [ "$code" = 200 ] && ! jq -e .apkName "$out/$other/latest.json" >/dev/null 2>&1; then
+  # A 200 that is not our JSON: Pages without a 404.html answers unknown paths
+  # with index.html. Nothing is published on that channel.
+  echo "No $other channel published yet (200 but no latest.json); skipping."
+  rm -rf "$out/$other"
 elif [ "$code" = 200 ]; then
   other_name="$(jq -er .apkName "$out/$other/latest.json")"
   curl -fsS -o "$out/$other/$other_name" "$base/$other/$other_name"

site/404.html

@@ -0,0 +1,3 @@
+<!doctype html>
+<html lang="en"><head><meta charset="utf-8"><title>Not found</title></head>
+<body><h1>404</h1><p>Not found. <a href="/">Pro Libertate Games downloads</a></p></body></html>