Build panel

The panel shows registered codex-on-crack runs: phases, agents, activity, recorded usage, routes (configured versus verified), and visual reviews. The user opens it from the sidebar or a thread tab (Codex on Crack), or in a browser through the localhost fallback.

Open the embedded view first

When the user asks to open or see the panel, call crack_panel. This is the MCP App surface, not a localhost browser tab. Do not start a browser server as the default. A request to explore an example can use crack_panel with demo: true; keep it explicitly labelled as generated data with no live work. Use the localhost fallback only when the native surface is unavailable or the user asks for a browser preview. State which surface actually opened.