Null bytes in API key values (introduced by copy-paste) crash
os.environ[k] = v with ValueError: embedded null byte, preventing
hermes from starting at all.
Hermes startup entrypoints now load ~/.hermes/.env and project fallback env files with user config taking precedence over stale shell-exported values. This makes model/provider/base URL changes in .env actually take effect after restarting Hermes. Adds a shared env loader plus regression coverage, and reproduces the original bug case where OPENAI_BASE_URL and HERMES_INFERENCE_PROVIDER remained stuck on old shell values before import.
