feat(environment): integrate reward_computer call in step() with mock fallback

feat(environment): integrate llm_pipeline call in step() with mock fallback

feat(environment): add conversation history builder from last 5 attack turns

feat(environment): add step() skeleton with active episode guard

feat(environment): call reward_computer.reset() in reset() to clear novelty scorer

feat(environment): implement reset() — zeros state and generates new episode_id

feat(environment): add set_llm_pipeline() injection method for Person 3

feat(environment): add set_reward_computer() injection method for Person 2

feat(environment): scaffold RedTeamEnvironment class with state fields

feat(config): add get_settings() with lru_cache for singleton pattern

feat(config): add LLM fields — hf_token, api_base_url, model_name, provider

feat(config): add Settings class extending pydantic BaseSettings

chore(server): add server package __init__.py