/claim #1850

Summary

Adds x.ai (Grok) provider support to Archestra.

Changes

• Add xai adapter (OpenAI-compatible at https://api.x.ai/v1)
• Add xai proxy routes with agent support
• Add xai chat integration
• Add grok model detection in detectProviderFromModel()
• Add config for XAI_API_KEY
• Add error handling using OpenAI parser
• Update E2E tests
• Update frontend types and components

Models Supported

• grok-4
• grok-4-1-fast-reasoning
• grok-4-1-fast-non-reasoning
• grok-code-fast-1

Testing

Get API key from https://console.x.ai/ and set XAI_API_KEY env var.

Closes #1850