fix: pause malformed scheduled tasks

src/task-scheduler.ts

@@ -14,6 +14,7 @@ import {
   getDueTasks,
   getTaskById,
   logTaskRun,
+  updateTask,
   updateTaskAfterRun,
 } from './db.js';
 import { GroupQueue } from './group-queue.js';
@@ -39,6 +40,8 @@ async function runTask(
     groupDir = resolveGroupFolderPath(task.group_folder);
   } catch (err) {
     const error = err instanceof Error ? err.message : String(err);
+    // Stop retry churn for malformed legacy rows.
+    updateTask(task.id, { status: 'paused' });
     logger.error(
       { taskId: task.id, groupFolder: task.group_folder, error },
       'Task has invalid group folder',
@@ -237,3 +240,8 @@ export function startSchedulerLoop(deps: SchedulerDependencies): void {
 
   loop();
 }
+
+/** @internal - for tests only. */
+export function _resetSchedulerLoopForTests(): void {
+  schedulerRunning = false;
+}