Refactor transcript fetching (#5)

* refactor: share transcript fetch helper

* Update lib/fetchTranscript.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update lib/fetchTranscript.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

lib/fetchTranscript.ts

@@ -0,0 +1,32 @@
+/**
+ * Fetches transcript content from a URL with optional authentication
+ * @param url The URL to fetch the transcript from
+ * @param username Optional username for Basic Auth
+ * @param password Optional password for Basic Auth
+ * @returns The transcript content or null if fetching fails
+ */
+export async function fetchTranscriptContent(
+  url: string,
+  username?: string,
+  password?: string
+): Promise<string | null> {
+  try {
+    const authHeader =
+      username && password
+        ? "Basic " + Buffer.from(`${username}:${password}`).toString("base64")
+        : undefined;
+
+    const response = await fetch(url, {
+      headers: authHeader ? { Authorization: authHeader } : {},
+    });
+
+    if (!response.ok) {
+      process.stderr.write(`Error fetching transcript from ${url}: ${response.statusText}\n`);
+      return null;
+    }
+    return await response.text();
+  } catch (error) {
+    process.stderr.write(`Failed to fetch transcript from ${url}: ${error}\n`);
+    return null;
+  }
+}