Add Karpathy LLM Wiki

Set up a persistent wiki knowledge base on NanoClaw, based on Karpathy's LLM Wiki pattern.

Each step is safe to re-run: directory creation uses mkdir -p, initial wiki files are created only if absent, the container skill is preserved unless the user opts to update it, and the group CLAUDE.md section is replaced in place via marker comments rather than duplicated.

Step 1: Read the pattern

Read ${CLAUDE_SKILL_DIR}/llm-wiki.md — this is the full LLM Wiki idea as written by Karpathy. Understand it thoroughly before proceeding. Summarize the core idea to the user briefly, then discuss what they want to build.

Step 2: Choose a group

AskUserQuestion: "Which group should have the wiki?"

1. Main group — add to your existing main chat
2. Dedicated group — create a new group just for the wiki
3. Other — pick an existing group

If dedicated: ask which channel and chat, then register with pnpm exec tsx setup/index.ts --step register.