Refactor ProfileForm to support draft state management and improve file handling

- Introduced functionality to save and restore form state as a draft when creating a new voice profile.
- Added helper functions for converting files to and from base64 format to facilitate file handling.
- Updated the API types to use a more flexible LanguageCode type for language parameters.
- Enhanced the UI store to manage profile form drafts, improving user experience during profile creation.

app/src/components/StoriesTab/StoryTrackEditor.tsx

@@ -565,7 +565,14 @@ export function StoryTrackEditor({ storyId, items }: StoryTrackEditorProps) {
 
     window.addEventListener('keydown', handleKeyDown);
     return () => window.removeEventListener('keydown', handleKeyDown);
-  }, [selectedClipId, handleSplit, handleDuplicate, handleDelete, setSelectedClipId, handlePlayPause]);
+  }, [
+    selectedClipId,
+    handleSplit,
+    handleDuplicate,
+    handleDelete,
+    setSelectedClipId,
+    handlePlayPause,
+  ]);
 
   // Add global mouse listeners for trimming
   useEffect(() => {