refactor: replace Loader2 with Spinner component across the application

This update standardizes the loading indicators by replacing all instances of Loader2 with the new Spinner component. The Spinner component provides a consistent look and feel for loading states throughout the UI, enhancing the user experience.

Changes include:
- Updated loading indicators in various components such as popovers, modals, and views.
- Ensured that the Spinner component is used with appropriate sizes for different contexts.

No functional changes were made; this is purely a visual and structural improvement.

apps/ui/src/components/views/code-view.tsx

@@ -4,7 +4,8 @@ import { useAppStore } from '@/store/app-store';
 import { getElectronAPI } from '@/lib/electron';
 import { Card, CardContent } from '@/components/ui/card';
 import { Button } from '@/components/ui/button';
-import { File, Folder, FolderOpen, ChevronRight, ChevronDown, RefreshCw, Code } from 'lucide-react';
+import { File, Folder, FolderOpen, ChevronRight, ChevronDown, Code } from 'lucide-react';
+import { Spinner } from '@/components/ui/spinner';
 import { cn } from '@/lib/utils';
 
 const logger = createLogger('CodeView');
@@ -206,7 +207,7 @@ export function CodeView() {
   if (isLoading) {
     return (
       <div className="flex-1 flex items-center justify-center" data-testid="code-view-loading">
-        <RefreshCw className="w-6 h-6 animate-spin text-muted-foreground" />
+        <Spinner size="lg" />
       </div>
     );
   }