feat(ui): add solid background color option for input prompt (#16563)

Co-authored-by: Alexander Farber <farber72@outlook.de>

packages/cli/src/ui/utils/terminalUtils.ts

@@ -0,0 +1,22 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import process from 'node:process';
+
+/**
+ * Returns the color depth of the current terminal.
+ * Returns 24 (TrueColor) if unknown or not a TTY.
+ */
+export function getColorDepth(): number {
+  return process.stdout.getColorDepth ? process.stdout.getColorDepth() : 24;
+}
+
+/**
+ * Returns true if the terminal has low color depth (less than 24-bit).
+ */
+export function isLowColorDepth(): boolean {
+  return getColorDepth() < 24;
+}