feat: apply durable event acknowledgements

internal/client/agent/handshake_test.go

@@ -118,6 +118,17 @@ func TestSendCommandEventCanonicalDigest_HP_EVENT_02(t *testing.T) {
 	}
 }
 
+func TestApplyEventAckValidatesAndReleasesPrefix_HP_EVENT_03(t *testing.T) {
+	store := &ackStore{}
+	ack := &rvboxv1.EventAck{IssueUuid: "019c46f1-1d02-7000-8000-000000000066", ThroughEventSeq: 4}
+	if err := ApplyEventAck(context.Background(), store, ack); err != nil || store.issue.String() != ack.IssueUuid || store.sequence != 4 {
+		t.Fatalf("ApplyEventAck = issue=%s sequence=%d err=%v", store.issue, store.sequence, err)
+	}
+	if err := ApplyEventAck(context.Background(), store, &rvboxv1.EventAck{IssueUuid: "bad", ThroughEventSeq: 1}); !errors.Is(err, ErrInvalidEventAck) {
+		t.Fatalf("invalid ack error = %v", err)
+	}
+}
+
 type fakeTransport struct {
 	written []byte
 	read    []byte
@@ -130,6 +141,16 @@ func (store *reconcileStore) DiscardTerminal(_ context.Context, issue domain.UUI
 	return nil
 }
 
+type ackStore struct {
+	issue    domain.UUID
+	sequence uint64
+}
+
+func (store *ackStore) Ack(_ context.Context, issue domain.UUID, sequence uint64) error {
+	store.issue, store.sequence = issue, sequence
+	return nil
+}
+
 func (transport *fakeTransport) Write(_ context.Context, value []byte) error {
 	transport.written = append([]byte(nil), value...)
 	return nil