refactor(downloader): 🔧 reorganize TrackStreamInfo class and imports

* Moved `TrackStreamInfo` class definition from `download.py` to `downloader.py`.
* Removed redundant `dataclass` import from `download.py`.
* Updated import statements to maintain clarity and organization.

tidal_dl_ng/model/downloader.py

@@ -2,6 +2,7 @@ import pathlib
 from dataclasses import dataclass
 
 from requests import HTTPError
+from tidalapi.media import Stream, StreamManifest
 
 
 @dataclass
@@ -11,3 +12,13 @@ class DownloadSegmentResult:
     path_segment: pathlib.Path
     id_segment: int
     error: HTTPError | None = None
+
+
+@dataclass
+class TrackStreamInfo:
+    """Container for track stream information."""
+
+    stream_manifest: StreamManifest | None
+    file_extension: str
+    requires_flac_extraction: bool
+    media_stream: Stream | None