feat(FN-3364): sort done tasks by most recent completion

- Sort Done column and list views by most recent completion timestamp to keep recent work visible first
- Update dashboard and task management docs to document done-column recency ordering behavior
- Preserve merge-active task state across verification bounce paths and board/list rendering updates
- Forward removeDependencyReferences in deleteTask flows and treat finish_reason=repeat as a soft-stop in engine executor

Fusion-Task-Id: FN-3364

docs/dashboard-guide.md

@@ -16,6 +16,7 @@ Features:
 - Inline quick entry creation
 - PR/issue badges with live updates
 - GitHub provenance marker on task cards imported from GitHub (`sourceType: github_import`), shown alongside existing footer metadata like timers
+- Column ordering semantics: `triage`, `todo`, `in-progress`, `in-review`, and `archived` stay priority-ordered; `done` is ordered by most recent completion first (`columnMovedAt`, then `updatedAt`, then `createdAt` fallback)
 
 ![Board view](./screenshots/dashboard-overview.png)
 

docs/task-management.md

@@ -86,6 +86,10 @@ Fusion task columns:
 5. **done** — merged/finalized
 6. **archived** — preserved history, optionally cleaned from filesystem
 
+Board ordering behavior:
+- Active work columns (`triage`, `todo`, `in-progress`, `in-review`) remain priority-ordered.
+- The `done` column is recency-ordered by completion time (newest first), using `columnMovedAt` as primary and falling back to `updatedAt` then `createdAt` for legacy tasks.
+
 ### Lifecycle commands
 
 ```bash

packages/dashboard/app/components/Board.tsx

@@ -82,8 +82,24 @@ function compareTaskIdNumeric(a: string, b: string): number {
   return a.localeCompare(b);
 }
 
+function getDoneSortTimestamp(task: Task): number {
+  const timestamp = task.columnMovedAt ?? task.updatedAt ?? task.createdAt;
+  const parsed = Date.parse(timestamp);
+  return Number.isFinite(parsed) ? parsed : 0;
+}
+
 function sortTasksForColumn(tasks: Task[], column: ColumnType): Task[] {
   return [...tasks].sort((a, b) => {
+    if (column === "done") {
+      const timestampCmp = getDoneSortTimestamp(b) - getDoneSortTimestamp(a);
+      if (timestampCmp !== 0) {
+        return timestampCmp;
+      }
+
+      // Deterministic tie-breaker when completion timestamps match.
+      return compareTaskIdNumeric(a.id, b.id);
+    }
+
     // In the in-review column, merging tasks stay pinned above non-merging tasks.
     if (column === "in-review") {
       const aIsMerging = a.status === "merging" || a.status === "merging-pr" || a.status === "merging-fix";
@@ -93,7 +109,7 @@ function sortTasksForColumn(tasks: Task[], column: ColumnType): Task[] {
       }
     }
 
-    // Primary sort: priority descending (urgent → high → normal → low).
+    // Primary sort for non-done columns: priority descending (urgent → high → normal → low).
     // compareTaskPriority normalizes missing/invalid values to `normal`.
     const priorityCmp = compareTaskPriority(a.priority, b.priority);
     if (priorityCmp !== 0) {

packages/dashboard/app/components/__tests__/Board.test.tsx

@@ -292,12 +292,99 @@ describe("Board", () => {
     });
 
     describe("sortTasksForColumn priority ordering", () => {
-      it("orders tasks by priority descending (urgent → high → normal → low)", () => {
+      it("orders done tasks by most recent completion regardless of priority", () => {
         const tasks: Task[] = [
-          createTask({ id: "FN-003", description: "Low task", column: "todo", priority: "low" }),
-          createTask({ id: "FN-001", description: "Urgent task", column: "todo", priority: "urgent" }),
-          createTask({ id: "FN-004", description: "Normal task", column: "todo", priority: "normal" }),
-          createTask({ id: "FN-002", description: "High task", column: "todo", priority: "high" }),
+          createTask({
+            id: "FN-003",
+            description: "Older urgent done task",
+            column: "done",
+            priority: "urgent",
+            columnMovedAt: "2024-01-01T09:00:00.000Z",
+          }),
+          createTask({
+            id: "FN-001",
+            description: "Newest low-priority done task",
+            column: "done",
+            priority: "low",
+            columnMovedAt: "2024-01-01T11:00:00.000Z",
+          }),
+          createTask({
+            id: "FN-002",
+            description: "Middle high-priority done task",
+            column: "done",
+            priority: "high",
+            columnMovedAt: "2024-01-01T10:00:00.000Z",
+          }),
+        ];
+
+        renderBoard({ tasks });
+
+        const doneTasks = JSON.parse(screen.getByTestId("column-done").getAttribute("data-tasks") || "[]") as Task[];
+        expect(doneTasks.map((t: Task) => t.id)).toEqual(["FN-001", "FN-002", "FN-003"]);
+      });
+
+      it("falls back to updatedAt and createdAt for legacy done tasks missing columnMovedAt", () => {
+        const tasks: Task[] = [
+          createTask({
+            id: "FN-010",
+            description: "Has updatedAt fallback",
+            column: "done",
+            updatedAt: "2024-01-01T10:30:00.000Z",
+          }),
+          createTask({
+            id: "FN-011",
+            description: "Has createdAt fallback",
+            column: "done",
+            createdAt: "2024-01-01T10:45:00.000Z",
+          }),
+          createTask({
+            id: "FN-012",
+            description: "Has real completion timestamp",
+            column: "done",
+            columnMovedAt: "2024-01-01T11:00:00.000Z",
+          }),
+        ];
+
+        const taskWithCreatedAtOnly = tasks[1];
+        delete taskWithCreatedAtOnly.columnMovedAt;
+        delete taskWithCreatedAtOnly.updatedAt;
+
+        renderBoard({ tasks });
+
+        const doneTasks = JSON.parse(screen.getByTestId("column-done").getAttribute("data-tasks") || "[]") as Task[];
+        expect(doneTasks.map((t: Task) => t.id)).toEqual(["FN-012", "FN-011", "FN-010"]);
+      });
+
+      it("keeps non-done columns priority-ordered even when recency differs", () => {
+        const tasks: Task[] = [
+          createTask({
+            id: "FN-003",
+            description: "Low but newest",
+            column: "todo",
+            priority: "low",
+            columnMovedAt: "2024-01-01T12:00:00.000Z",
+          }),
+          createTask({
+            id: "FN-001",
+            description: "Urgent but older",
+            column: "todo",
+            priority: "urgent",
+            columnMovedAt: "2024-01-01T10:00:00.000Z",
+          }),
+          createTask({
+            id: "FN-004",
+            description: "Normal",
+            column: "todo",
+            priority: "normal",
+            columnMovedAt: "2024-01-01T11:00:00.000Z",
+          }),
+          createTask({
+            id: "FN-002",
+            description: "High",
+            column: "todo",
+            priority: "high",
+            columnMovedAt: "2024-01-01T09:00:00.000Z",
+          }),
         ];
 
         renderBoard({ tasks, searchQuery: "task" });