feat: improve kanban implementation

src/services/bucket.js

@@ -18,7 +18,7 @@ export default class BucketService extends AbstractService {
 
 	beforeUpdate(model) {
 		const taskService = new TaskService()
-		model.tasks = model.tasks.map(t => taskService.processModel(t))
+		model.tasks = model.tasks?.map(t => taskService.processModel(t))
 		return model
 	}
 }

src/services/task.js

@@ -37,7 +37,8 @@ export default class TaskService extends AbstractService {
 		return this.processModel(model)
 	}
 
-	processModel(model) {
+	processModel(updatedModel) {
+		const model = { ...updatedModel }
 
 		model.title = model.title?.trim()