When _seed_from_env() reads API keys to populate the credential pool, it
should treat ~/.hermes/.env as the authoritative source — not os.environ.
Stale env vars inherited from parent shell processes (Codex CLI, test
scripts, etc.) can shadow deliberate changes to the .env file, causing
auth.json to cache an outdated key that leads to silent 401 errors.
This is especially visible with OpenRouter: if a parent process exported
OPENROUTER_API_KEY=test-key-fresh and the user later updates .env with a
valid key, restarting Hermes still picks up the stale os.environ value,
writes it back to auth.json, and all API calls fail with 401.
Fixes#18254
2ef1ad280b