Replace embedded mermaid with rendered PNG images

- Render KQVI puzzle dependency chart as PNG (preview + full-size)
- Replace mermaid code block with image embed linking to full version
- Remove broken mermaid-lightbox.js from book.toml and delete file
- Update Chart Configuration section (was Mermaid Configuration)
- Images copied to src/inspiration/ for mdbook build

book.toml

@@ -7,7 +7,7 @@ description = "A taxonomy of puzzle design patterns from classic point-and-click
 [output.html]
 git-repository-url = "https://github.com/noti/puzzle-design-kb"
 edit-url-template = "https://github.com/noti/puzzle-design-kb/edit/main/{path}"
-additional-js = ["mermaid.min.js", "mermaid-init.js", "mermaid-lightbox.js"]
+additional-js = ["mermaid.min.js", "mermaid-init.js"]
 
 [output.html.playground]
 editable = true