optimize rate limiting hook for body-based user identification

Added Rate limiting using Redis

fix: add promptHash to logger for easy replay

fix: log error for eigencloud providers

feat: Added eigen cloud API support for deterministic llm rersult

chore: update docs

feat: add provider clients, chat service and define endpoints in the server

feat: add fastify server

feat: add utils (rate/concurrency limiters, HMAC, JSON validator)

feat: add config loading and model catalog

Initial Commit