Fail loudly when release uploads do not land

Follow-up to the publishing fix: CI created the v0.2.11 release and logged each
upload, but the assets never arrived, so the job looked successful while the
release was empty. The host root filesystem is full (7.8G, 100%), and Gitea
answered HTTP 500 "Attachments.Save: no space left on device".

- publish_release.sh now checks the HTTP status of every asset upload and prints the
  response body on failure, then verifies the release reports as many assets as were
  sent. Empty releases can no longer pass silently.
- Deleted the empty v0.2.11 release so the "latest" release (v0.2.10) still has all
  five artifacts; the tag itself remains.
- TODO/MEMORY record the host disk blocker with concrete cleanup commands and note
  that v0.2.11 artifacts are built locally in build/ for upload once space exists.

tools/publish_release.sh

@@ -99,8 +99,31 @@ for f in "${all_artifacts[@]}"; do
     exit 1
   fi
   echo "==> Uploading $(basename "$f")"
-  curl -s -X POST "$API/$RELEASE_ID/assets" "${AUTH[@]}" -F "attachment=@$f" >/dev/null
+  # Fail loudly: a silent 4xx here used to leave a release with no artifacts while
+  # the job still reported success.
+  code="$(curl -sS -o /tmp/release-upload.json -w '%{http_code}' --retry 2 \
+    -X POST "$API/$RELEASE_ID/assets" "${AUTH[@]}" -F "attachment=@$f" || true)"
+  if [[ "$code" != "201" && "$code" != "200" ]]; then
+    echo "error: upload of $(basename "$f") failed with HTTP $code" >&2
+    cat /tmp/release-upload.json >&2 || true
+    echo "" >&2
+    exit 1
+  fi
 done
 
+# Verify the release actually carries the artifacts we just sent.
+have="$(curl -sS "${AUTH[@]}" "$API/$RELEASE_ID" | python3 -c "
+import sys, json
+try:
+    d = json.load(sys.stdin)
+except Exception:
+    print(0); raise SystemExit
+print(len(d.get('assets', [])))" 2>/dev/null || echo 0)"
+if [[ "${have:-0}" -lt "${#all_artifacts[@]}" ]]; then
+  echo "error: release has $have assets, expected ${#all_artifacts[@]}" >&2
+  exit 1
+fi
+echo "Verified $have artifacts on the release"
+
 echo ""
 echo "Release live: $HOST/$REPO/releases/tag/$TAG"