fix: make worker handoff rotation durable

internal/orchestrator/rotation_test.go

@@ -708,6 +708,7 @@ type activityAdapter struct {
 	activityErr  error
 	reasonAsked  []string
 	deadEndsSeen []continuity.DeadEnd
+	observed     chan struct{}
 }
 
 func (a *activityAdapter) Activity(context.Context, herdr.Session) ([]herdr.ToolCall, error) {
@@ -717,6 +718,12 @@ func (a *activityAdapter) Activity(context.Context, herdr.Session) ([]herdr.Tool
 func (a *activityAdapter) RequestHandoffReason(_ context.Context, _ herdr.Session, reason string, deadEnds []continuity.DeadEnd) error {
 	a.reasonAsked = append(a.reasonAsked, reason)
 	a.deadEndsSeen = deadEnds
+	if a.observed != nil {
+		select {
+		case a.observed <- struct{}{}:
+		default:
+		}
+	}
 	return nil
 }
 
@@ -764,7 +771,7 @@ func TestActivityTriggersRequestReasonedHandoffWithoutReleasing(t *testing.T) {
 	}
 
 	t.Run("thrash requests a reasoned handoff and does not release, via TurnDecision", func(t *testing.T) {
-		a := &activityAdapter{fakeAdapter: fakeAdapter{occupancy: 0, boundary: true}, calls: thrashCalls}
+		a := &activityAdapter{fakeAdapter: fakeAdapter{occupancy: 0, boundary: true}, calls: thrashCalls, observed: make(chan struct{}, 1)}
 		c, st, task := newCoordinator(a)
 		decision, err := c.TurnDecision(context.Background(), task.ID)
 		if err != nil {
@@ -862,13 +869,15 @@ func TestActivityTriggersRequestReasonedHandoffWithoutReleasing(t *testing.T) {
 		c, st, task := newCoordinator(a)
 
 		ctx, cancel := context.WithCancel(context.Background())
-		defer cancel()
-		go c.Monitor(ctx, .8, time.Millisecond)
+		done := make(chan error, 1)
+		go func() { done <- c.Monitor(ctx, .8, time.Millisecond) }()
 
-		deadline := time.Now().Add(300 * time.Millisecond)
-		for time.Now().Before(deadline) && len(a.reasonAsked) == 0 {
-			time.Sleep(time.Millisecond)
+		select {
+		case <-a.observed:
+		case <-time.After(300 * time.Millisecond):
 		}
+		cancel()
+		<-done
 		if len(a.reasonAsked) == 0 || a.reasonAsked[0] != "thrash" {
 			t.Fatalf("reasonAsked=%v want a thrash request from rotate()", a.reasonAsked)
 		}
@@ -959,10 +968,17 @@ func (w specWorktrees) Spec(domain.Task) (string, string, bool)             { re
 type conventionsAdapter struct {
 	fakeAdapter
 	notifications int
+	observed      chan struct{}
 }
 
 func (a *conventionsAdapter) NotifyConventionsChanged(context.Context, herdr.Session) error {
 	a.notifications++
+	if a.observed != nil {
+		select {
+		case a.observed <- struct{}{}:
+		default:
+		}
+	}
 	return nil
 }
 
@@ -991,7 +1007,7 @@ func TestConventionsDriftNotifiesActiveSession(t *testing.T) {
 		t.Fatal(err)
 	}
 	task := s.Tasks()[0]
-	a := &conventionsAdapter{fakeAdapter: fakeAdapter{occupancy: 0}}
+	a := &conventionsAdapter{fakeAdapter: fakeAdapter{occupancy: 0}, observed: make(chan struct{}, 1)}
 	c := &orchestrator.Coordinator{Store: s, Worktrees: specWorktrees{wtPath: worktree, repoPath: repo}, Adapters: adapters{a}, StatePath: t.TempDir() + "/sessions.json"}
 
 	leaseEvt, err := s.Lease(task.ID, "h1", time.Minute)
@@ -1003,8 +1019,8 @@ func TestConventionsDriftNotifiesActiveSession(t *testing.T) {
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	go c.Monitor(ctx, .8, time.Millisecond)
+	done := make(chan error, 1)
+	go func() { done <- c.Monitor(ctx, .8, time.Millisecond) }()
 
 	time.Sleep(50 * time.Millisecond)
 	if a.notifications != 0 {
@@ -1015,10 +1031,12 @@ func TestConventionsDriftNotifiesActiveSession(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	deadline := time.Now().Add(time.Second)
-	for time.Now().Before(deadline) && a.notifications == 0 {
-		time.Sleep(time.Millisecond)
+	select {
+	case <-a.observed:
+	case <-time.After(time.Second):
 	}
+	cancel()
+	<-done
 	if a.notifications == 0 {
 		t.Fatal("session was never notified of the conventions-doc update")
 	}