Fix: [2.0.8] process=False로 포맷 처리 건너뛰고 자막만 추출

extract_info에 process=False 적용하여 포맷 선택 단계를 완전히 스킵.
자막 정보는 YouTube extractor에서 직접 반환되므로 포맷 처리 불필요.

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

app/transcript.py

@@ -23,13 +23,8 @@ def fetch_transcript(video_id: str) -> str:
 
     ydl_opts = {
         "skip_download": True,
-        "writeautomaticsub": True,
-        "subtitleslangs": ["ko", "en"],
-        "subtitlesformat": "json3",
         "quiet": True,
         "no_warnings": True,
-        "extract_flat": False,
-        "ignore_no_formats_error": True,
     }
 
     if os.path.isfile(COOKIES_SRC):
@@ -39,7 +34,7 @@ def fetch_transcript(video_id: str) -> str:
 
     try:
         with yt_dlp.YoutubeDL(ydl_opts) as ydl:
-            info = ydl.extract_info(url, download=False)
+            info = ydl.extract_info(url, ie_key="Youtube", download=False, process=False)
     finally:
         if "cookiefile" in ydl_opts:
             os.unlink(ydl_opts["cookiefile"])