chore(tui): remove dead branch cleanup code

- drop unused TUI helpers, test-only layout scaffolding, and stale public debug exports
- remove an unused profiler import and trim test-only coverage for deleted helpers

ui-tui/src/lib/virtualHeights.ts

@@ -2,7 +2,7 @@ import type { Msg } from '../types.js'
 
 import { boundedHistoryRenderText } from './text.js'
 
-export const hashText = (text: string) => {
+const hashText = (text: string) => {
   let h = 5381
 
   for (let i = 0; i < text.length; i++) {