feat(project) : add delete button for empty projects with confirmation modal

Adds taskCount virtual field on Project entity, delete button in ProjectDrawer
(visible only when taskCount === 0), and a reusable ConfirmDeleteProjectModal.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/components/project/ProjectDrawer.vue

@@ -64,7 +64,7 @@
             </div>
         </form>
 
-        <div v-if="isEditing && project" class="mt-6 border-t border-neutral-200 pt-4">
+        <div v-if="isEditing && project" class="mt-6 border-t border-neutral-200 pt-4 flex items-center justify-between">
             <button
                 class="flex items-center gap-2 text-sm text-neutral-500 hover:text-amber-600"
                 :disabled="isSubmitting"
@@ -73,7 +73,21 @@
                 <Icon :name="project.archived ? 'mdi:archive-arrow-up-outline' : 'mdi:archive-arrow-down-outline'" size="18" />
                 {{ project.archived ? 'Désarchiver' : 'Archiver' }}
             </button>
+            <button
+                v-if="project.taskCount === 0"
+                class="flex items-center gap-2 text-sm text-neutral-500 hover:text-red-600"
+                :disabled="isSubmitting"
+                @click="confirmDeleteOpen = true"
+            >
+                <Icon name="mdi:delete-outline" size="18" />
+                {{ $t('common.delete') }}
+            </button>
         </div>
+
+        <ConfirmDeleteProjectModal
+            v-model="confirmDeleteOpen"
+            @confirm="handleDelete"
+        />
     </AppDrawer>
 </template>
 
@@ -104,6 +118,7 @@ const isOpen = computed({
 
 const isEditing = computed(() => !!props.project)
 const isSubmitting = ref(false)
+const confirmDeleteOpen = ref(false)
 
 const { listRepositories } = useGiteaService()
 const giteaRepos = ref<GiteaRepository[]>([])
@@ -164,7 +179,7 @@ watch(() => props.modelValue, (open) => {
     }
 })
 
-const { create, update } = useProjectService()
+const { create, update, remove } = useProjectService()
 
 async function handleSubmit() {
     touched.name = true
@@ -213,6 +228,19 @@ async function handleSubmit() {
     }
 }
 
+async function handleDelete() {
+    if (!props.project) return
+    isSubmitting.value = true
+    try {
+        await remove(props.project.id)
+        emit('saved')
+        isOpen.value = false
+    } finally {
+        confirmDeleteOpen.value = false
+        isSubmitting.value = false
+    }
+}
+
 async function handleArchiveToggle() {
     if (!props.project) return
     isSubmitting.value = true