feat: enhance worktree listing by scanning external directories

- Implemented a new function to scan the .worktrees directory for worktrees that may exist outside of git's management, allowing for better detection of externally created or corrupted worktrees.
- Updated the /list endpoint to include discovered worktrees in the response, improving the accuracy of the worktree listing.
- Added logging for discovered worktrees to aid in debugging and tracking.
- Cleaned up and organized imports in the list.ts file for better maintainability.

apps/ui/src/components/views/board-view/kanban-board.tsx

@@ -99,7 +99,7 @@ export function KanbanBoard({
   const { columnWidth, containerStyle } = useResponsiveKanban(columns.length);
 
   return (
-    <div className="flex-1 overflow-x-auto px-5 pb-4 relative" style={backgroundImageStyle}>
+    <div className="flex-1 overflow-x-auto px-5 pt-4 pb-4 relative" style={backgroundImageStyle}>
       <DndContext
         sensors={sensors}
         collisionDetection={collisionDetectionStrategy}