feat: implement 'not_started' task status with validation and UI updates

src/components/ProjectTasksList.js

@@ -135,9 +135,10 @@ export default function ProjectTasksList() {
 				groups.completed.push(taskWithStatus);
 			} else if (task.status === "in_progress") {
 				groups.in_progress.push(taskWithStatus);
-			} else {
+			} else if (task.status === "pending") {
 				groups.pending.push(taskWithStatus);
 			}
+			// not_started tasks are not displayed in the UI
 		});
 
 		// Sort pending tasks by date_added (newest first)

src/components/TaskStatusDropdownSimple.js

@@ -25,6 +25,10 @@ export default function TaskStatusDropdown({
 	}, []);
 
 	const statusConfig = {
+		not_started: {
+			label: t("taskStatus.not_started"),
+			variant: "secondary",
+		},
 		pending: {
 			label: t("taskStatus.pending"),
 			variant: "warning",