Create or fix llms.txt and llms-full.txt files for a documentation project, following the llmstxt.org specification. Use this skill whenever someone needs to create an llms.txt file, generate a full documentation text dump (llms-full.txt), or fix a malformed llms.txt. Also use when optimizing a docs site for AI crawlers, when setting up AI discoverability files, or when the user mentions making their docs readable by LLMs, ChatGPT, Perplexity, or other AI systems.