🐛 fix(thirdparty): preserve manifest during snapshot update

.gitea/ci/update_thirdparty_skills.sh

@@ -99,15 +99,30 @@ cd "$REPO_DIR"
 git config user.name "$COMMIT_AUTHOR_NAME"
 git config user.email "$COMMIT_AUTHOR_EMAIL"
 
-git fetch origin "$TARGET_BRANCH"
-git checkout -B "$TARGET_BRANCH" "origin/$TARGET_BRANCH"
-
 tmp_dir="$(mktemp -d)"
 cleanup() {
   rm -rf "$tmp_dir"
 }
 trap cleanup EXIT
 
+if [ ! -f "$MANIFEST_PATH" ]; then
+  echo "ERROR: third-party manifest not found: $MANIFEST_PATH" >&2
+  exit 1
+fi
+
+manifest_copy="$tmp_dir/thirdparty_skills.json"
+cp "$MANIFEST_PATH" "$manifest_copy"
+MANIFEST_PATH="$manifest_copy"
+
+git fetch origin "$TARGET_BRANCH"
+git checkout -B "$TARGET_BRANCH" "origin/$TARGET_BRANCH"
+
+sources_file="$tmp_dir/sources.tsv"
+if ! emit_sources_tsv > "$sources_file"; then
+  echo "ERROR: failed to load third-party manifest: $MANIFEST_PATH" >&2
+  exit 1
+fi
+
 changed=0
 while IFS=$'\t' read -r source_id upstream_repo upstream_ref snapshot_dir sync_mode; do
   [ -n "$source_id" ] || continue
@@ -167,7 +182,7 @@ EOF
 
   git add -A "$snapshot_dir"
   changed=1
-done < <(emit_sources_tsv)
+done < "$sources_file"
 
 if [ "$changed" -eq 0 ] || git diff --cached --quiet; then
   echo "All third-party snapshots are up to date."