chore: add sync-md-to-wechat utility script

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/sync-md-to-wechat.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+SRC="$REPO_ROOT/skills/baoyu-markdown-to-html/scripts/md/"
+DEST="$REPO_ROOT/skills/baoyu-post-to-wechat/scripts/md/"
+
+echo "Syncing: $SRC → $DEST"
+
+rsync -av --delete \
+  --exclude 'node_modules/' \
+  --exclude 'package-lock.json' \
+  "$SRC" "$DEST"
+
+echo "Installing dependencies..."
+cd "$DEST" && npm install
+
+echo "Done."