Semantic folder index for codebase navigation. Generates index.toon files with concise folder summaries ordered by importance, enabling fast LLM codebase traversal without reading every file. Commands: /toondex (create initial index), /redex (update with changes). Use when the user wants to index a codebase, understand project structure, map codebase folders, index project layout, navigate a large codebase, understand folder structure, or asks about /toondex or /redex commands.