LLM chat completions x402 REST usage
LLM inference and AI chat over x402: OpenAI-compatible chat completion for $0.002: gpt-oss-120b by default, or gpt-oss-20b, llama-3.3-70b, llama-3.1-8b, qwen3-30b. POST {model, messages}; up to 1,024 output tokens, tools...