API key selection is now base_url-aware: when the resolved base_url
targets OpenRouter, OPENROUTER_API_KEY takes priority (preserving the
#289 fix). When hitting any other endpoint (Z.ai, vLLM, custom, etc.),
OPENAI_API_KEY takes priority so the OpenRouter key doesn't leak.
Applied in both the runtime provider resolver (the real code path) and
the CLI initial default (for consistency).
Fixes#560.
When both OPENROUTER_API_KEY and OPENAI_API_KEY are set (e.g. OPENAI_API_KEY
in .bashrc), the wrong key was sent to OpenRouter causing auth failures.
Fixed key resolution order in cli.py and runtime_provider.py.
Fixes#289
Updated the authentication mechanism to store Codex OAuth tokens in the Hermes auth store located at ~/.hermes/auth.json instead of the previous ~/.codex/auth.json. This change includes refactoring related functions for reading and saving tokens, ensuring better management of authentication states and preventing conflicts between different applications. Adjusted tests to reflect the new storage structure and improved error handling for missing or malformed tokens.