refactor: add openclaw metadata and rename SKILL_DIR to baseDir across all skills

skills/baoyu-xhs-images/references/workflows/prompt-assembly.md

@@ -213,11 +213,12 @@ When generating multiple images in a series:
 1. **Image 1 (cover)**: Generate without `--ref` — this establishes the visual anchor
 2. **Images 2+**: Always pass image 1 as `--ref` to the image generation skill:
    ```bash
-   ${BUN_X} ${SKILL_DIR}/scripts/main.ts \
+   ${BUN_X} <image-skill-baseDir>/scripts/main.ts \
      --promptfiles prompts/02-content-xxx.md \
      --ref path/to/01-cover-xxx.png \
      --image 02-content-xxx.png --ar 3:4 --quality 2k
    ```
+   Replace `<image-skill-baseDir>` with the installed image generation skill directory.
    This ensures the AI maintains the same character design, illustration style, and color rendering across the series.
 
 ### Step 6: Combine