- Fix broken symlink for 09_convolutions_ABOUT.md
- Fix header level warnings (H1 to H3 jumps) in community.md and intro.md
- Remove broken cross-references to deleted files across site pages
- Fix lexing errors by using text blocks for Unicode characters
- Update mermaid diagram in big-picture.md to use light fill colors
for PDF compatibility (mermaid-cli does not respect inline color styles)