feat: provide way to build and attach platforms

scripts/attach-asset.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+# Attach files to an existing Gitea release, found by tag. Re-runnable: an
+# asset of the same name is replaced. Use this to add a build CI can't produce
+# (e.g., the macOS arm64 bundle, built on a Mac) to a release CI already made.
+#
+# Required env:
+#   GITEA_API    e.g., https://git.scient.ing/api/v1/repos/<owner>/<repo>
+#   GITEA_TOKEN  a token with contents:write
+#   TAG          the release tag the assets belong to
+#   ASSETS       space-separated list of files to upload
+# Optional env:
+#   JQ           jq command (default: jq); on a Mac without jq, set to
+#                "pixi exec --spec jq -- jq"
+
+set -euo pipefail
+: "${GITEA_API:?}"; : "${GITEA_TOKEN:?}"; : "${TAG:?}"; : "${ASSETS:?}"
+: "${JQ:=jq}"
+auth="Authorization: token ${GITEA_TOKEN}"
+
+rid="$(curl -fsSL -H "$auth" "${GITEA_API}/releases/tags/${TAG}" | $JQ -r '.id')"
+[ -n "$rid" ] && [ "$rid" != "null" ] || { echo "no release found for tag ${TAG}" >&2; exit 1; }
+
+for f in $ASSETS; do
+  n="$(basename "$f")"
+  for aid in $(curl -fsSL -H "$auth" "${GITEA_API}/releases/${rid}/assets" \
+                 | $JQ -r --arg n "$n" '.[] | select(.name==$n) | .id'); do
+    curl -fsSL -X DELETE -H "$auth" "${GITEA_API}/releases/${rid}/assets/${aid}" || true
+  done
+  echo "uploading $n to release ${TAG}"
+  curl -fsSL -X POST -H "$auth" -F "attachment=@${f}" \
+    "${GITEA_API}/releases/${rid}/assets?name=${n}"
+done
+