feat(ui): replace native confirm() with DaisyUI modal composable (F7.2)

Create useConfirm composable (promise-based, singleton state) and
ConfirmModal component. Replace all 10 confirm()/window.confirm() calls
across 9 pages and 1 composable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/pages/profiles/manage.vue

@@ -169,8 +169,10 @@ const create = async () => {
   }
 }
 
+const { confirm } = useConfirm()
+
 const remove = async (profileId) => {
-  if (!confirm('Supprimer ce profil ?')) { return }
+  if (!await confirm({ message: 'Supprimer ce profil ?' })) { return }
   deleting.value = profileId
   try {
     await deleteProfile(profileId)