API key authentication failure when using custom providers and multiple agents/routes

Users are encountering 401 (Unauthorized) errors when configuring `inkos` with custom LLM providers and multiple agents/routes, despite `inkos.json` showing correct API key configurations. The issue suggests API keys are not being properly mounted or passed during actual requests, even after successful `set-model` commands. The pain point is a critical authentication breakdown, preventing access to configured LLM services and halting all generation processes. Market implication: Robust and flexible API key management is fundamental for SaaS platforms integrating diverse LLM ecosystems. Failures in handling custom provider authentication, especially with advanced configurations like multi-agent routing, severely limit extensibility and user adoption, indicating a need for more transparent and reliable credential handling mechanisms.