feat: Add directory listing functionality

- Add `list_dir` function to `Workspace` struct
- Implement path handling and directory scanning logic
- Refine struct formatting for `Node`, `ComputeSlice`, `StorageSlice`
- Update `StorageSlice.pricing_policy` comment
- Adjust whitespace in CSS styles

lib/web/ui/static/css/main.css

@@ -192,15 +192,15 @@ code {
     transform: translateX(-100%);
     transition: transform 0.3s ease;
   }
-  
+
   .sidebar.show {
     transform: translateX(0);
   }
-  
+
   .main {
     margin-left: 0;
   }
-  
+
   .mobile-menu-toggle {
     display: block;
     position: fixed;
@@ -262,17 +262,18 @@ code {
 
 /* Print styles */
 @media print {
+
   .sidebar,
   .header,
   .theme-toggle {
     display: none !important;
   }
-  
+
   .main {
     margin-left: 0 !important;
     padding: 0 !important;
   }
-  
+
   body {
     padding-top: 0 !important;
   }