feat: setup Next.js frontend structure

frontend/src/components/EpisodePlayer.tsx

@@ -0,0 +1,87 @@
+import React, { useState } from "react";
+
+interface Episode {
+  id: string;
+  title: string;
+  pubDate: string;
+  audioPath: string;
+  sourceLink: string;
+}
+
+export default function EpisodePlayer() {
+  const [episodes, setEpisodes] = useState<Episode[]>([]);
+  const [selectedEpisode, setSelectedEpisode] = useState<Episode | null>(null);
+  const [isPlaying, setIsPlaying] = useState(false);
+  const [audioUrl, setAudioUrl] = useState<string | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    fetchEpisodes();
+  }, []);
+
+  const fetchEpisodes = async () => {
+    try {
+      const response = await fetch("/api/episodes");
+      if (!response.ok) {
+        throw new Error("エピソードの取得に失敗しました");
+      }
+      const data = await response.json();
+      setEpisodes(data);
+      setLoading(false);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "エラーが発生しました");
+      setLoading(false);
+    }
+  };
+
+  const handlePlay = (episode: Episode) => {
+    setSelectedEpisode(episode);
+    setAudioUrl(`/podcast_audio/${episode.id}.mp3`);
+    setIsPlaying(true);
+  };
+
+  if (loading) return <div>読み込み中...</div>;
+  if (error) return <div className="text-red-500">エラー: {error}</div>;
+
+  return (
+    <div className="space-y-4">
+      <h3 className="text-lg font-medium">最近のエピソード</h3>
+      <div className="space-y-2">
+        {episodes.map((episode) => (
+          <div
+            key={episode.id}
+            className="flex justify-between items-center p-2 hover:bg-gray-50 rounded"
+          >
+            <span>{episode.title}</span>
+            <button
+              onClick={() => handlePlay(episode)}
+              className="px-3 py-1 bg-blue-500 text-white rounded hover:bg-blue-600"
+            >
+              再生
+            </button>
+          </div>
+        ))}
+      </div>
+
+      {selectedEpisode && (
+        <div className="mt-6">
+          <h4 className="text-md font-semibold mb-2">
+            再生中: {selectedEpisode.title}
+          </h4>
+          {audioUrl ? (
+            <audio
+              src={audioUrl}
+              controls
+              className="w-full"
+              onPlay={() => setIsPlaying(true)}
+              onPause={() => setIsPlaying(false)}
+            />
+          ) : (
+            <div>音声ファイルを読み込み中...</div>
+          )}
+        </div>
+      )}
+    </div>
+  );
+}