Piped input (#104)

* New method for handling stdin. Bypass Ink, and output to stdout. Makes the CLI work like a typical Unix application when called with piped input.

* Fixing a few post-merge errors.

* Format code.

* Clean up lint and format errors.

packages/cli/src/utils/readStdin.ts

@@ -0,0 +1,27 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+export async function readStdin(): Promise<string> {
+  return new Promise((resolve, reject) => {
+    let data = '';
+    process.stdin.setEncoding('utf8');
+
+    process.stdin.on('readable', () => {
+      let chunk;
+      while ((chunk = process.stdin.read()) !== null) {
+        data += chunk;
+      }
+    });
+
+    process.stdin.on('end', () => {
+      resolve(data);
+    });
+
+    process.stdin.on('error', (err) => {
+      reject(err);
+    });
+  });
+}