feat: add downloader module with yt-dlp integration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/downloader.py

@@ -0,0 +1,46 @@
+import os
+import yt_dlp
+from typing import Optional
+
+
+def download_space(
+    space_url: str,
+    output_dir: str,
+    cookies_file: Optional[str] = None
+) -> str:
+    """
+    Downloads X Space recording using yt-dlp.
+
+    Args:
+        space_url: URL of the X Space recording
+        output_dir: Directory to save the MP3 file
+        cookies_file: Optional path to cookies file for authentication
+
+    Returns:
+        Path to the downloaded MP3 file
+    """
+    # Extract space ID from URL for filename
+    space_id = space_url.split('/')[-1]
+
+    # Configure yt-dlp options
+    ydl_opts = {
+        'format': 'bestaudio/best',
+        'outtmpl': os.path.join(output_dir, f'space_{space_id}.%(ext)s'),
+        'postprocessors': [{
+            'key': 'FFmpegExtractAudio',
+            'preferredcodec': 'mp3',
+        }],
+        'quiet': False,
+        'no_warnings': False,
+    }
+
+    # Add cookies if provided
+    if cookies_file:
+        ydl_opts['cookiefile'] = cookies_file
+
+    # Download with yt-dlp
+    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
+        ydl.extract_info(space_url, download=True)
+
+    # Return the expected output path
+    return os.path.join(output_dir, f'space_{space_id}.mp3')