feat: add chalkboard style and xhs-images previews

- Add chalkboard style to baoyu-xhs-images and baoyu-comic
- Update chalkboard style for article-illustrator, cover-image, infographic
- Remove tech style from baoyu-xhs-images
- Add style and layout preview screenshots for xhs-images
- Bump version to 1.9.0

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -6,7 +6,7 @@
   },
   "metadata": {
     "description": "Skills shared by Baoyu for improving daily work efficiency",
-    "version": "1.8.0"
+    "version": "1.9.0"
   },
   "plugins": [
     {