fix: move DownloadService to session Context to prevent worker registration crash

DownloadService was instantiated every time the download_episodes menu
was entered, unconditionally registering a worker on the global
ThreadManager singleton. The second download in the same session would
crash with "Worker with name 'download_worker' already registered".

Move DownloadService to a lazy property on Context (as the existing
TODO suggested), matching the pattern used by all other services.

viu_media/cli/interactive/menu/media/download_episodes.py

@@ -8,7 +8,6 @@ def download_episodes(ctx: Context, state: State) -> State | InternalDirective:
     """Menu to select and download episodes synchronously."""
     from viu_media.cli.utils.search import find_best_match_title
     from .....core.utils.normalizer import normalize_title
-    from ....service.download.service import DownloadService
 
     feedback = ctx.feedback
     selector = ctx.selector
@@ -71,16 +70,11 @@ def download_episodes(ctx: Context, state: State) -> State | InternalDirective:
         feedback.info("No episodes selected for download.")
         return InternalDirective.BACK
 
-    # Step 3: Download episodes synchronously
-    # TODO: move to main ctx
-    download_service = DownloadService(
-        config, ctx.media_registry, ctx.media_api, ctx.provider
-    )
-
+    # Step 3: Download episodes synchronously using the session-scoped service
     feedback.info(
         f"Starting download of {len(selected_episodes)} episodes. This may take a while..."
     )
-    download_service.download_episodes_sync(media_item, selected_episodes)
+    ctx.download.download_episodes_sync(media_item, selected_episodes)
 
     feedback.success(f"Finished downloading {len(selected_episodes)} episodes.")
 

viu_media/cli/interactive/session.py

@@ -16,6 +16,7 @@ if TYPE_CHECKING:
     from ...libs.provider.anime.base import BaseAnimeProvider
     from ...libs.selectors.base import BaseSelector
     from ..service.auth import AuthService
+    from ..service.download.service import DownloadService
     from ..service.feedback import FeedbackService
     from ..service.player import PlayerService
     from ..service.registry import MediaRegistryService
@@ -86,6 +87,7 @@ class Context:
     _selector: Optional["BaseSelector"] = None
     _media_api: Optional["BaseApiClient"] = None
 
+    _download: Optional["DownloadService"] = None
     _feedback: Optional["FeedbackService"] = None
     _media_registry: Optional["MediaRegistryService"] = None
     _watch_history: Optional["WatchHistoryService"] = None
@@ -137,6 +139,16 @@ class Context:
 
         return self._media_api
 
+    @property
+    def download(self) -> "DownloadService":
+        if not self._download:
+            from ..service.download.service import DownloadService
+
+            self._download = DownloadService(
+                self.config, self.media_registry, self.media_api, self.provider
+            )
+        return self._download
+
     @property
     def player(self) -> "PlayerService":
         if not self._player: