fix(tui): clear Apple Terminal resize artifacts

Use a deeper alt-screen clear for Apple Terminal resize repaints so host reflow artifacts do not survive the recovery frame.

ui-tui/packages/hermes-ink/src/ink/ink.tsx

@@ -73,7 +73,13 @@ import {
   startSelection,
   updateSelection
 } from './selection.js'
-import { supportsExtendedKeys, SYNC_OUTPUT_SUPPORTED, type Terminal, writeDiffToTerminal } from './terminal.js'
+import {
+  needsAltScreenResizeScrollbackClear,
+  supportsExtendedKeys,
+  SYNC_OUTPUT_SUPPORTED,
+  type Terminal,
+  writeDiffToTerminal
+} from './terminal.js'
 import {
   CURSOR_HOME,
   cursorMove,
@@ -82,7 +88,8 @@ import {
   DISABLE_MODIFY_OTHER_KEYS,
   ENABLE_KITTY_KEYBOARD,
   ENABLE_MODIFY_OTHER_KEYS,
-  ERASE_SCREEN
+  ERASE_SCREEN,
+  ERASE_SCROLLBACK
 } from './termio/csi.js'
 import {
   DBP,
@@ -121,6 +128,11 @@ const ERASE_THEN_HOME_PATCH = Object.freeze({
   content: ERASE_SCREEN + CURSOR_HOME
 })
 
+const DEEP_ERASE_THEN_HOME_PATCH = Object.freeze({
+  type: 'stdout' as const,
+  content: ERASE_SCREEN + ERASE_SCROLLBACK + CURSOR_HOME
+})
+
 // Cached per-Ink-instance, invalidated on resize. frame.cursor.y for
 // alt-screen is always terminalRows - 1 (renderer.ts).
 function makeAltScreenParkPatch(terminalRows: number) {
@@ -863,17 +875,17 @@ export default class Ink {
       // position independently. Parking at bottom (not 0,0) keeps the guide
       // where the user's attention is.
       //
-      // After resize, prepend ERASE_SCREEN too. The diff only writes cells
+      // After resize, prepend a clear too. The diff only writes cells
       // that changed; cells where new=blank and prev-buffer=blank get skipped
       // — but the physical terminal still has stale content there (shorter
-      // lines at new width leave old-width text tails visible). ERASE inside
-      // BSU/ESU is atomic: old content stays visible until the whole
-      // erase+paint lands, then swaps in one go. Writing ERASE_SCREEN
-      // synchronously in handleResize would blank the screen for the ~80ms
-      // render() takes.
+      // lines at new width leave old-width text tails visible). Apple Terminal
+      // can also preserve alt-screen reflow artifacts in scrollback during
+      // resize, so it gets CSI 3J in this one recovery path. When BSU/ESU is
+      // supported, the clear+paint lands atomically; otherwise the final state
+      // is still healed even if the repaint is visible.
       if (this.needsEraseBeforePaint) {
         this.needsEraseBeforePaint = false
-        optimized.unshift(ERASE_THEN_HOME_PATCH)
+        optimized.unshift(needsAltScreenResizeScrollbackClear() ? DEEP_ERASE_THEN_HOME_PATCH : ERASE_THEN_HOME_PATCH)
       } else {
         optimized.unshift(CURSOR_HOME_PATCH)
       }

ui-tui/packages/hermes-ink/src/ink/terminal.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it } from 'vitest'
+
+import { needsAltScreenResizeScrollbackClear } from './terminal.js'
+
+describe('terminal resize quirks', () => {
+  it('uses a deeper alt-screen resize clear for Apple Terminal', () => {
+    expect(needsAltScreenResizeScrollbackClear({ TERM_PROGRAM: 'Apple_Terminal' })).toBe(true)
+    expect(needsAltScreenResizeScrollbackClear({ TERM_PROGRAM: ' Apple_Terminal ' })).toBe(true)
+  })
+
+  it('keeps the normal resize repaint path for modern terminals', () => {
+    expect(needsAltScreenResizeScrollbackClear({ TERM_PROGRAM: 'vscode' })).toBe(false)
+    expect(needsAltScreenResizeScrollbackClear({ TERM_PROGRAM: 'iTerm.app' })).toBe(false)
+  })
+})

ui-tui/packages/hermes-ink/src/ink/terminal.ts

@@ -168,6 +168,10 @@ export function isXtermJs(): boolean {
   return xtversionName?.startsWith('xterm.js') ?? false
 }
 
+export function needsAltScreenResizeScrollbackClear(env: NodeJS.ProcessEnv = process.env): boolean {
+  return (env.TERM_PROGRAM ?? '').trim() === 'Apple_Terminal'
+}
+
 // Terminals known to correctly implement the Kitty keyboard protocol
 // (CSI >1u) and/or xterm modifyOtherKeys (CSI >4;2m) for ctrl+shift+<letter>
 // disambiguation. We previously enabled unconditionally (#23350), assuming