debug: log yt-dlp stderr to diagnose extraction failures

app/downloader.py

@@ -43,8 +43,6 @@ async def extract_audio(url: str) -> Path:
 
     cmd = [
         "yt-dlp",
-        "--no-warnings",
-        "--quiet",
         "--extract-audio",
         "--audio-format", "mp3",
         "--audio-quality", "128K",
@@ -64,9 +62,14 @@ async def extract_audio(url: str) -> Path:
         stderr=asyncio.subprocess.PIPE,
     )
     _, stderr = await proc.communicate()
+    stderr_text = stderr.decode().strip()
+
+    if stderr_text:
+        import logging
+        logging.getLogger(__name__).warning("yt-dlp stderr: %s", stderr_text)
 
     if proc.returncode != 0:
-        raise RuntimeError(stderr.decode().strip() or "yt-dlp failed with no output")
+        raise RuntimeError(stderr_text or "yt-dlp failed with no output")
 
     if expected.exists():
         return expected