feat : add project archiving feature

Allow projects to be archived/unarchived from the ProjectDrawer, with a
toggle filter on the projects page to show/hide archived projects.

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

frontend/components/project/ProjectDrawer.vue

@@ -53,6 +53,17 @@
                 </button>
             </div>
         </form>
+
+        <div v-if="isEditing && project" class="mt-6 border-t border-neutral-200 pt-4">
+            <button
+                class="flex items-center gap-2 text-sm text-neutral-500 hover:text-amber-600"
+                :disabled="isSubmitting"
+                @click="handleArchiveToggle"
+            >
+                <Icon :name="project.archived ? 'mdi:archive-arrow-up-outline' : 'mdi:archive-arrow-down-outline'" size="18" />
+                {{ project.archived ? 'Désarchiver' : 'Archiver' }}
+            </button>
+        </div>
     </AppDrawer>
 </template>
 
@@ -171,6 +182,21 @@ async function handleSubmit() {
     }
 }
 
+async function handleArchiveToggle() {
+    if (!props.project) return
+    isSubmitting.value = true
+    try {
+        const newArchived = !props.project.archived
+        await update(props.project.id, { archived: newArchived }, {
+            toastSuccessKey: newArchived ? 'projects.archived' : 'projects.unarchived',
+        })
+        emit('saved')
+        isOpen.value = false
+    } finally {
+        isSubmitting.value = false
+    }
+}
+
 onMounted(async () => {
     try {
         giteaRepos.value = await listRepositories()