h2oGPTe GitHub Action for AI code review

Introduced the h2oGPTe GitHub Action, enabling AI-powered code review, suggestions, and automated pull request generation directly within GitHub. The action integrates with air-gapped or managed h2oGPTe instances for enhanced security. Key technical implementation detail: pre-fetching GitHub event data and conditioning the agent on this context to mitigate high token usage and slow response times observed with autonomous data fetching.