Add xAI Grok as an LLM provider

[calesthio]

Summary

Add xAI Grok as a supported LLM provider in Crucix.

Crucix already supports multiple providers (anthropic, openai, gemini, codex, openrouter, minimax, mistral). Grok would be a useful addition for contributors and operators who already use xAI models and want another option for briefing synthesis, alert evaluation, and idea generation.

Proposed scope

• add grok / xAI provider wiring to the LLM abstraction
• support environment-based configuration in the same style as existing providers
• define a sensible default model
• document setup in README.md / env docs
• add provider tests comparable to the other LLM integrations

Expected implementation areas

• provider selection / dispatch
• request formatting and auth headers
• model default and model override handling
• any provider-specific response parsing
• tests for normal request/response behavior
• optional env-gated integration test if the repo pattern already supports that

Acceptance criteria

• LLM_PROVIDER=grok works for the same flows as other providers
• failures degrade gracefully and do not crash sweeps
• docs explain required env vars and model defaults
• tests pass and match the repo?s current LLM provider patterns

Notes

Please follow the existing provider implementation style instead of introducing a one-off path. If someone in the community wants to pick this up, comment on the issue and go for it.

[3byss]

Can I give this a try?

[Johnyyy1]

Can i give this a try? I can do that easily and im bored. :D