Add retry utility with exponential backoff

src/utils/retry.ts

@@ -0,0 +1,28 @@
+/**
+ * Retry an async function with exponential backoff.
+ */
+export async function retry<T>(
+  fn: () => Promise<T>,
+  maxAttempts: number = 3,
+  baseDelayMs: number = 1000
+): Promise<T> {
+  let lastError: Error | undefined;
+
+  for (let attempt = 0; attempt < maxAttempts; attempt++) {
+    try {
+      return await fn();
+    } catch (err) {
+      lastError = err instanceof Error ? err : new Error(String(err));
+      if (attempt < maxAttempts) {
+        const delay = baseDelayMs * Math.pow(2, attempt);
+        await sleep(delay);
+      }
+    }
+  }
+
+  throw lastError;
+}
+
+function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}