feat(cli): add output formatting helpers

packages/cli/src/output.ts

@@ -0,0 +1,27 @@
+/**
+ * Print JSON to stdout (for --json mode).
+ */
+export function printJson(data: unknown): void {
+  console.log(JSON.stringify(data));
+}
+
+/**
+ * Print human-readable text to stdout.
+ */
+export function printText(text: string): void {
+  console.log(text);
+}
+
+/**
+ * Log to stderr (progress, errors — never pollutes stdout).
+ */
+export function log(message: string): void {
+  console.error(message);
+}
+
+/**
+ * Convert epoch ms timestamp to ISO 8601 string.
+ */
+export function msToIso(ms: number): string {
+  return new Date(ms).toISOString();
+}