Component model

A plugin registers a renderer-neutral definition and a readonly MayflyUiNode snapshot with a Mayfly service.

domain state / dsh projection
            │ set(data/replace)
     registry snapshot
            │
 frontend interaction owner
    draft / action / feedback
            │
   core admission + compile
            │
       pi-tui component

The plugin owns domain state and its definition. The registry owns the current registration snapshot, the frontend owner keeps semantic interaction state for that registration instance, and core owns only compiled components, editor bindings, focus, layout, and width.

Rules:

• nodes contain no Agent, Session, terminal width, or renderer object;
• onEvent.observe receives editing facts; onEvent.action performs native reads or writes and returns a structured settlement;
• context carries source stamps, operation ID, revision, AbortSignal, and a progress reporter;
• external domain changes use set(node, { reason: 'data', source }); instance replacement uses reason: 'replace'; handlers do not echo drafts through set;
• Fiber unload removes the registration and invalidates late handlers, reports, and publishers;
• every visible component stays bounded at 20/40/80/120 columns.

See the UI node reference for fields.