- Add slug/short_id fields to database with auto-generation

- Create migration script for existing data
- Update admin interface to show only short URLs
- Implement redirect system to avoid code duplication
- Maintain backward compatibility with old URLs

src/app/admin/page.tsx

@@ -10,6 +10,7 @@ import { Button } from '@/components/ui/button';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
 import { Badge } from '@/components/ui/badge';
 import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
 import { Progress } from '@/components/ui/progress';
 import Navigation from '@/components/Navigation';
 import AuthGuard from '@/components/AuthGuard';
@@ -324,14 +325,14 @@ function AdminPageContent() {
                         <Input
                           type="text"
                           readOnly
-                          value={`${window.location.origin}/campaigns/${campaign.id}/propose`}
+                          value={`${window.location.origin}/p/${campaign.slug || 'campagne'}`}
                           className="flex-1 text-sm bg-white dark:bg-slate-800 border-blue-300 dark:border-blue-600 text-blue-700 dark:text-blue-300 font-mono"
                         />
                         <Button
                           variant={copiedCampaignId === campaign.id ? "default" : "outline"}
                           size="sm"
                           onClick={() => {
-                            copyToClipboard(`${window.location.origin}/campaigns/${campaign.id}/propose`, campaign.id);
+                            copyToClipboard(`${window.location.origin}/p/${campaign.slug || 'campagne'}`, campaign.id);
                           }}
                           className="text-xs"
                         >