fix:STT V2 기본 리전을 싱가포르(asia-southeast1)로 변경

Chirp 2 지원 리전: us-central1, europe-west4, asia-southeast1
서울(asia-northeast3)은 Chirp 2 미지원

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config/services.php

@@ -47,7 +47,7 @@
     'google' => [
         'credentials_path' => env('GOOGLE_APPLICATION_CREDENTIALS'),
         'storage_bucket' => env('GOOGLE_STORAGE_BUCKET'),
-        'location' => env('GOOGLE_STT_LOCATION', 'asia-northeast3'),
+        'location' => env('GOOGLE_STT_LOCATION', 'asia-southeast1'),
     ],
 
     /*