test(tui): remove stale turn freeze experiment

ui-tui/src/__tests__/turnStore.test.ts

@@ -1,27 +0,0 @@
-import { describe, expect, it } from 'vitest'
-
-import {
-  freezeTurnRendering,
-  getRenderableTurnState,
-  patchTurnState,
-  resetTurnState,
-  unfreezeTurnRendering
-} from '../app/turnStore.js'
-
-describe('turn render freezing', () => {
-  it('holds the render snapshot stable while live turn state keeps changing', () => {
-    resetTurnState()
-    patchTurnState({ streaming: 'before scroll' })
-    freezeTurnRendering()
-
-    patchTurnState({ reasoning: 'new thinking', streaming: 'new streamed text' })
-
-    expect(getRenderableTurnState().streaming).toBe('before scroll')
-    expect(getRenderableTurnState().reasoning).toBe('')
-
-    unfreezeTurnRendering()
-
-    expect(getRenderableTurnState().streaming).toBe('new streamed text')
-    expect(getRenderableTurnState().reasoning).toBe('new thinking')
-  })
-})