Add activity history clearing

internal/queue/queue.go

@@ -151,6 +151,15 @@ func (q *Queue) UpdateActive(id string, update func(*model.Run)) bool {
 	return true
 }
 
+func (q *Queue) ClearHistory() int {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+	count := len(q.history)
+	q.history = nil
+	q.emitLocked()
+	return count
+}
+
 func (q *Queue) snapshotLocked() []model.Run {
 	result := append([]model.Run{}, q.history...)
 	if q.active != nil {

internal/queue/queue_test.go

@@ -28,3 +28,34 @@ func TestQueueDeduplicatesJobAndRunsTask(t *testing.T) {
 	}
 	q.Stop()
 }
+
+func TestClearHistoryKeepsActiveAndPendingRuns(t *testing.T) {
+	started := make(chan struct{})
+	release := make(chan struct{})
+	q := New(func(_ context.Context, run model.Run) model.Run {
+		close(started)
+		<-release
+		run.Status = "success"
+		return run
+	}, nil)
+	q.RestoreHistory([]model.Run{{ID: "old", Status: "success"}})
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	go q.Run(ctx)
+	if err := q.Enqueue(model.Run{ID: "active", JobID: "active-job"}); err != nil {
+		t.Fatal(err)
+	}
+	<-started
+	if err := q.Enqueue(model.Run{ID: "pending", JobID: "pending-job"}); err != nil {
+		t.Fatal(err)
+	}
+	if cleared := q.ClearHistory(); cleared != 1 {
+		t.Fatalf("cleared = %d", cleared)
+	}
+	runs := q.Snapshot()
+	if len(runs) != 2 || runs[0].ID != "active" || runs[1].ID != "pending" {
+		t.Fatalf("runs = %#v", runs)
+	}
+	q.Stop()
+	close(release)
+}