fix: resolve build errors and warnings

frontend/src/components/EpisodePlayer.tsx

@@ -1,3 +1,5 @@
+"use client";
+
 import React, { useState } from "react";
 
 interface Episode {

frontend/src/components/FeedList.tsx

@@ -1,3 +1,5 @@
+"use client";
+
 import React, { useEffect, useState } from "react";
 
 interface FeedItem {