feat: support year directory structure and auto-create missing folders

Author: shimomo

scraper.php

@@ -34,5 +34,5 @@
 // 日付付きの JSON ファイルとして保存（例: docs/v2/20250826.json）
 // 最新データとして today.json にも保存
 $storage = new ProgramStorage();
-$storage->save($programs, "docs/{$version}/" . $date->format('Ymd') . '.json');
+$storage->save($programs, "docs/{$version}/" . $date->format('Y') . '/' . $date->format('Ymd') . '.json');
 $storage->save($programs, "docs/{$version}/today.json");

src/ProgramStorage.php

@@ -56,7 +56,16 @@ final class ProgramStorage
     public function save(array $programs, string $path): void
     {
         $contents = json_encode(['programs' => $programs]);
-        if ($contents !== false && file_put_contents($path, $contents) === false) {
+        if ($contents === false) {
+            throw new \RuntimeException("Failed to encode programs to JSON");
+        }
+
+        $dir = dirname($path);
+        if (!is_dir($dir) && !mkdir($dir, 0777, true) && !is_dir($dir)) {
+            throw new \RuntimeException("Failed to create directory: {$dir}");
+        }
+
+        if (file_put_contents($path, $contents) === false) {
             throw new \RuntimeException("Failed to save programs to {$path}");
         }
     }