fix(gitea): document and explain HTTP 422 repo is empty on release create

Co-authored-by: Cursor <cursoragent@cursor.com>

tools/fractured-launcher-electron/scripts/upload-release-to-gitea.sh

@@ -47,6 +47,12 @@ elif [ "$code" = "404" ]; then
   if [ "$code" != "201" ] && [ "$code" != "200" ]; then
     echo "Gitea create release failed HTTP $code:" >&2
     cat "$REL_JSON" >&2
+    if [ "$code" = "422" ] && jq -e '.message == "repo is empty"' "$REL_JSON" >/dev/null 2>&1; then
+      echo >&2
+      echo "Gitea does not allow releases on a repo with zero commits. Fix: push at least one commit" >&2
+      echo "to ${GITEA_OWNER}/${GITEA_REPO} (e.g. add README.md on branch ${TARGET} via web UI or git push)," >&2
+      echo "or set Actions variable GITEA_TARGET_REF to an existing default branch name." >&2
+    fi
     exit 1
   fi
   rel_id=$(jq -r '.id' "$REL_JSON")