LLM Core: agents.md & llms.txt

LLM Core generates your Shopify store's agents.md, telling AI agents (ChatGPT, Claude, Perplexity, Gemini, Shop Pay) how to browse your catalog, reach UCP/MCP endpoints, and respect checkout consent. Configure brand safety, AI licensing, and custom rules directly from the app, then sync to your theme in one click. Legacy /llms.txt and /llms-full.txt are retained for compatibility, while /robots.txt controls 17 known bots. Everything stays as Liquid templates: no proxy, no speed impact.