feat(task) : add markdown preview for task description

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

frontend/components/task/TaskModal.vue

@@ -196,9 +196,20 @@
 
                         <!-- Description -->
                         <div class="mt-5">
+                            <div class="mb-1 flex items-center justify-between">
+                                <label class="text-sm font-medium text-slate-700">Description</label>
+                                <button
+                                    v-if="form.description"
+                                    type="button"
+                                    class="flex items-center gap-1 rounded-md px-2 py-1 text-xs font-medium text-slate-500 transition-colors hover:bg-slate-100 hover:text-slate-700"
+                                    @click="showMarkdownPreview = true"
+                                >
+                                    <Icon name="heroicons:eye" class="size-3.5" />
+                                    Aperçu MD
+                                </button>
+                            </div>
                             <MalioInputTextArea
                                 v-model="form.description"
-                                label="Description"
                                 :size="5"
                                 resize="vertical"
                                 :min-resize-height="140"
@@ -206,6 +217,12 @@
                             />
                         </div>
 
+                        <MarkdownPreviewModal
+                            v-model="showMarkdownPreview"
+                            :content="form.description"
+                            title="Aperçu de la description"
+                        />
+
                         <!-- Documents -->
                         <TaskDocumentUpload
                             v-if="isEditing && task && isAdmin"
@@ -541,7 +558,7 @@ const isOpen = computed({
 })
 
 function close() {
-    if (confirmDeleteDocOpen.value || confirmDeleteOpen.value) return
+    if (confirmDeleteDocOpen.value || confirmDeleteOpen.value || showMarkdownPreview.value) return
     isOpen.value = false
 }
 
@@ -549,6 +566,7 @@ const isEditing = computed(() => !!props.task)
 const isSubmitting = ref(false)
 const confirmDeleteOpen = ref(false)
 const activeTab = ref<'details' | 'planning'>('details')
+const showMarkdownPreview = ref(false)
 
 const giteaUrl = ref('')
 const { getSettings: getGiteaSettings } = useGiteaService()