feat(HAI-100): add columnMovedAt timestamp and sort board tasks by move order

- Add columnMovedAt field to task types
- Set columnMovedAt on task creation and column moves in store
- Sort tasks by columnMovedAt descending in Board component
- Add store tests for columnMovedAt behavior

packages/core/src/store.test.ts

@@ -611,4 +611,42 @@ describe("TaskStore", () => {
       expect(logs[4].text).toBe("chunk 4");
     });
   });
+
+  describe("columnMovedAt", () => {
+    it("createTask sets columnMovedAt", async () => {
+      const before = new Date().toISOString();
+      const task = await store.createTask({ description: "test columnMovedAt" });
+      const after = new Date().toISOString();
+      expect(task.columnMovedAt).toBeDefined();
+      expect(task.columnMovedAt! >= before).toBe(true);
+      expect(task.columnMovedAt! <= after).toBe(true);
+    });
+
+    it("moveTask sets columnMovedAt to a recent ISO timestamp", async () => {
+      const task = await store.createTask({ description: "move test", column: "triage" });
+      const originalMovedAt = task.columnMovedAt;
+
+      // Small delay to ensure timestamp differs
+      await new Promise((r) => setTimeout(r, 10));
+
+      const before = new Date().toISOString();
+      const moved = await store.moveTask(task.id, "todo");
+      const after = new Date().toISOString();
+
+      expect(moved.columnMovedAt).toBeDefined();
+      expect(moved.columnMovedAt! >= before).toBe(true);
+      expect(moved.columnMovedAt! <= after).toBe(true);
+      expect(moved.columnMovedAt).not.toBe(originalMovedAt);
+    });
+
+    it("updateTask does NOT change columnMovedAt", async () => {
+      const task = await store.createTask({ description: "no change test" });
+      const originalMovedAt = task.columnMovedAt;
+
+      await new Promise((r) => setTimeout(r, 10));
+
+      const updated = await store.updateTask(task.id, { title: "new title" });
+      expect(updated.columnMovedAt).toBe(originalMovedAt);
+    });
+  });
 });

packages/core/src/store.ts

@@ -188,6 +188,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       steps: [],
       currentStep: 0,
       log: [{ timestamp: now, action: "Task created" }],
+      columnMovedAt: now,
       createdAt: now,
       updatedAt: now,
     };
@@ -263,7 +264,8 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
 
       const fromColumn = task.column;
       task.column = toColumn;
-      task.updatedAt = new Date().toISOString();
+      task.columnMovedAt = new Date().toISOString();
+      task.updatedAt = task.columnMovedAt;
 
       // Clear transient fields when moving to done (matches moveToDone behavior)
       if (toColumn === "done") {
@@ -605,7 +607,8 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     task.worktree = undefined;
     task.status = undefined;
     task.blockedBy = undefined;
-    task.updatedAt = new Date().toISOString();
+    task.columnMovedAt = new Date().toISOString();
+    task.updatedAt = task.columnMovedAt;
 
     await this.atomicWriteTaskJson(dir, task);
 

packages/core/src/types.ts

@@ -57,6 +57,9 @@ export interface Task {
   log: TaskLogEntry[];
   size?: "S" | "M" | "L";
   reviewLevel?: number;
+  /** ISO-8601 timestamp of when the task last entered its current column.
+   *  Used to sort cards within a column so that recently-moved cards appear at the top. */
+  columnMovedAt?: string;
   createdAt: string;
   updatedAt: string;
 }

packages/dashboard/app/components/Board.tsx

@@ -24,7 +24,18 @@ export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast
         <Column
           key={col}
           column={col}
-          tasks={tasks.filter((t) => t.column === col)}
+          tasks={tasks
+            .filter((t) => t.column === col)
+            .sort((a, b) => {
+              // Tasks with columnMovedAt sort descending (most recent first)
+              // Tasks without it (legacy) fall to the bottom, sorted by createdAt ascending
+              if (a.columnMovedAt && b.columnMovedAt) {
+                return b.columnMovedAt.localeCompare(a.columnMovedAt);
+              }
+              if (a.columnMovedAt && !b.columnMovedAt) return -1;
+              if (!a.columnMovedAt && b.columnMovedAt) return 1;
+              return a.createdAt.localeCompare(b.createdAt);
+            })}
           allTasks={tasks}
           maxConcurrent={maxConcurrent}
           onMoveTask={onMoveTask}