fix(knowledge): task cards showed 'LIST' badge instead of 'Task'

The type-badge template had no v-else-if for task, so tasks fell
through to the v-else which renders 'List'.

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

frontend/src/views/KnowledgeView.vue

@@ -539,6 +539,7 @@ onUnmounted(() => {
               <span v-if="item.note_type === 'note'">Note</span>
               <span v-else-if="item.note_type === 'person'">Person</span>
               <span v-else-if="item.note_type === 'place'">Place</span>
+              <span v-else-if="item.note_type === 'task'">Task</span>
               <span v-else>List</span>
             </span>