fix(tui): harden Terminal.app render behavior

Avoid Terminal.app paint corruption by disabling fast-echo in that terminal, sanitizing non-SGR control sequences before ANSI rendering, and defaulting Apple Terminal back to the safer 256-color path unless truecolor is explicitly requested.

ui-tui/src/lib/forceTruecolor.ts

@@ -19,12 +19,42 @@ export function shouldForceTruecolor(env: NodeJS.ProcessEnv = process.env): bool
   return TRUE_RE.test(override)
 }
 
+const isAppleTerminal = (env: NodeJS.ProcessEnv = process.env) => (env.TERM_PROGRAM ?? '').trim() === 'Apple_Terminal'
+
+const isAdvertisedTruecolor = (env: NodeJS.ProcessEnv = process.env) => {
+  const colorTerm = (env.COLORTERM ?? '').trim().toLowerCase()
+  const forceColor = (env.FORCE_COLOR ?? '').trim()
+
+  return colorTerm === 'truecolor' || colorTerm === '24bit' || forceColor === '3'
+}
+
+export function shouldDowngradeAppleTerminalTruecolor(env: NodeJS.ProcessEnv = process.env): boolean {
+  if (!isAppleTerminal(env)) {
+    return false
+  }
+
+  if (shouldForceTruecolor(env)) {
+    return false
+  }
+
+  return isAdvertisedTruecolor(env)
+}
+
 if (shouldForceTruecolor()) {
   if (!process.env.COLORTERM) {
     process.env.COLORTERM = 'truecolor'
   }
 
   process.env.FORCE_COLOR = '3'
+} else if (shouldDowngradeAppleTerminalTruecolor()) {
+  // Terminal.app may advertise truecolor even when RGB SGR paths render
+  // incorrectly. Keep Hermes on the safer TERM-driven 256-color path unless
+  // users explicitly opt back in via HERMES_TUI_TRUECOLOR=1.
+  delete process.env.COLORTERM
+
+  if ((process.env.FORCE_COLOR ?? '').trim() === '3') {
+    delete process.env.FORCE_COLOR
+  }
 }
 
 export {}

ui-tui/src/lib/text.ts

@@ -9,12 +9,27 @@ import { VERBS } from '../content/verbs.js'
 import type { ThinkingMode } from '../types.js'
 
 const ESC = String.fromCharCode(27)
-const ANSI_RE = new RegExp(`${ESC}\\[[0-9;]*m`, 'g')
+const BEL = String.fromCharCode(7)
+const ANSI_CSI_RE = new RegExp(`${ESC}\\[[0-?]*[ -/]*[@-~]`, 'g')
+const ANSI_CSI_WITH_CMD_RE = new RegExp(`${ESC}\\[[0-?]*[ -/]*([@-~])`, 'g')
+const ANSI_OSC_RE = new RegExp(`${ESC}\\][\\s\\S]*?(?:${BEL}|${ESC}\\\\)`, 'g')
+const ANSI_STRING_RE = new RegExp(`${ESC}[PX^_][\\s\\S]*?(?:${BEL}|${ESC}\\\\)`, 'g')
+const ANSI_STRAY_ESC_RE = new RegExp(`${ESC}(?!\\[)[\\s\\S]?`, 'g')
+const CONTROL_RE = /[\x00-\x08\x0B\x0C\x0E-\x1A\x1C-\x1F\x7F]/g
 const WS_RE = /\s+/g
 
-export const stripAnsi = (s: string) => s.replace(ANSI_RE, '')
+export const stripAnsi = (s: string) =>
+  s.replace(ANSI_OSC_RE, '').replace(ANSI_STRING_RE, '').replace(ANSI_CSI_RE, '').replace(ANSI_STRAY_ESC_RE, '').replace(CONTROL_RE, '')
 
-export const hasAnsi = (s: string) => s.includes(`${ESC}[`) || s.includes(`${ESC}]`)
+export const sanitizeAnsiForRender = (s: string) =>
+  s
+    .replace(ANSI_OSC_RE, '')
+    .replace(ANSI_STRING_RE, '')
+    .replace(ANSI_CSI_WITH_CMD_RE, (seq, cmd: string) => (cmd === 'm' ? seq : ''))
+    .replace(ANSI_STRAY_ESC_RE, '')
+    .replace(CONTROL_RE, '')
+
+export const hasAnsi = (s: string) => s.includes(ESC)
 
 const renderEstimateLine = (line: string) => {
   const trimmed = line.trim()