Extend _check_providers() in system.py to report diagnostic status for
all 9 providers supported by ProviderRegistry: OpenAI, Anthropic, Google,
Azure, OpenRouter, Gemini, Cohere, Groq, and Together AI.
Previously only 4 providers (OpenAI, Anthropic, Google, OpenRouter) were
checked, leaving users of Groq, Together AI, Cohere, Azure, and Gemini
with no diagnostic feedback about their provider configuration.
Changes:
- Add Azure (AZURE_OPENAI_API_KEY), Gemini (GEMINI_API_KEY),
Cohere (COHERE_API_KEY), Groq (GROQ_API_KEY), and
Together AI (TOGETHER_API_KEY) to the provider_checks list
- Add Behave feature file with 11 scenarios covering all 9 providers
(presence, OK status when configured, WARN with recommendation when not)
ISSUES CLOSED: #3422
