Add support for OpenAI Codex CLI (Rust-Based) with Support for AgentAPI web chat UI

• Modify coder/agentAPI if needed to support rust-based Codex
• Ensure task reporting works properly in Coder + Tasks UI
• Add a demo to show how it works with the tasks template
• Add the module that uses the Codex CLI
• Record a short video showing it working with Coder Tasks and doing status reporting
• Address the points in Improve docs/UX for using AI modules with Tasks #259