fix(git-gate): reject AGit review refs

bot_bottle/gateway/git_gate/render.py

@@ -252,6 +252,23 @@ cat > "$refs_file"
 
 zero=0000000000000000000000000000000000000000
 
+# AGit creates pull requests by pushing to refs/for/* (with refs/draft/*
+# and refs/for-review/* aliases). Those server-owned review refs are not
+# ordinary repository branches and leave the resulting PR without a
+# branch that the bottle can update later. Require the normal
+# push-branch-then-open-PR workflow instead. Deletion remains allowed so
+# operators can clean up refs created before this guard existed.
+while IFS=' ' read -r old new ref; do
+  [ -z "$ref" ] && continue
+  [ "$new" = "$zero" ] && continue
+  case "$ref" in
+    refs/for/*|refs/draft/*|refs/for-review/*)
+      echo "git-gate: AGit review refs are disabled; push to refs/heads/<branch> and open the pull request from that branch" >&2
+      exit 1
+      ;;
+  esac
+done < "$refs_file"
+
 supervise_gitleaks_allow() {
   log_opts=$1
   ref=$2