fix(tui): reset terminal modes on startup and exit

Reset sticky mouse/focus/paste terminal modes before the TUI starts and during graceful shutdown paths so stale tab state from prior crashes cannot poison the next session.

ui-tui/src/lib/terminalModes.ts

@@ -0,0 +1,41 @@
+import { writeSync } from 'node:fs'
+
+export const TERMINAL_MODE_RESET =
+  '\x1b[?1006l' + // SGR mouse
+  '\x1b[?1003l' + // any-motion mouse
+  '\x1b[?1002l' + // button-motion mouse
+  '\x1b[?1000l' + // click mouse
+  '\x1b[?1004l' + // focus events
+  '\x1b[?2004l' + // bracketed paste
+  '\x1b[?1049l' + // alternate screen
+  '\x1b[0m' + // attributes
+  '\x1b[?25h' // cursor visible
+
+type ResettableStream = Pick<NodeJS.WriteStream, 'isTTY' | 'write'> & {
+  fd?: number
+}
+
+export function resetTerminalModes(stream: ResettableStream = process.stdout): boolean {
+  if (!stream.isTTY) {
+    return false
+  }
+
+  const fd = typeof stream.fd === 'number' ? stream.fd : stream === process.stdout ? 1 : undefined
+  if (fd !== undefined) {
+    try {
+      writeSync(fd, TERMINAL_MODE_RESET)
+
+      return true
+    } catch {
+      // Fall through to stream.write for mocked or unusual TTY streams.
+    }
+  }
+
+  try {
+    stream.write(TERMINAL_MODE_RESET)
+
+    return true
+  } catch {
+    return false
+  }
+}