Add GetTransactionsStream RPC (#345)

* RPC GetPaymentsStream

This introduces a new feature to the ArkService API that allows clients to subscribe to payment events. Here's a breakdown of the changes:

1. **OpenAPI Specification (`service.swagger.json`):**
   - A new endpoint `/v1/payments` is added to the API, supporting a `GET` operation for streaming payment events.
   - New definitions `v1GetPaymentsStreamResponse`, `v1RoundPayment`, and `v1AsyncPayment` are added to describe the structure of the streaming responses.

2. **Protobuf Definition (`service.proto`):**
   - Added a new RPC method `GetPaymentsStream` that streams `GetPaymentsStreamResponse` messages.
   - Defined new message types: `GetPaymentsStreamRequest`, `GetPaymentsStreamResponse`, `RoundPayment`, and `AsyncPayment`.

3. **Generated Protobuf Code (`service.pb.go`, `service.pb.gw.go`, `service_grpc.pb.go`):**
   - The generated code is updated to include the new RPC method and message types.
   - The gateway code includes functions to handle HTTP requests and responses for the new streaming endpoint.

4. **Application Logic (`covenant.go`, `covenantless.go`):**
   - New payment events channels are introduced (`paymentEventsCh`).
   - Payment events are propagated to these channels when a round is finalized or an async payment is completed.
   - New event types `RoundPaymentEvent` and `AsyncPaymentEvent` are defined, implementing a `PaymentEvent` interface.

5. **gRPC Handlers (`arkservice.go`):**
   - Added logic to handle `GetPaymentsStream` requests and manage payment listeners.
   - A new goroutine is started to listen to payment events and forward them to active listeners.

Overall, this patch extends the ArkService to support real-time streaming of payment events, allowing clients to receive updates on both round payments and async payments as they occur.

* Move emit events in updateVtxoSet & Use generics and parsers (#1)

* Move sending event to updateVtxoSet

* Use generics and parsers

* pr review refactor

* pr review refactor

* fix

---------

Co-authored-by: Pietralberto Mazza <18440657+altafan@users.noreply.github.com>

server/internal/core/application/covenantless.go

@@ -42,7 +42,8 @@ type covenantlessService struct {
 	paymentRequests *paymentsMap
 	forfeitTxs      *forfeitTxsMap
 
-	eventsCh chan domain.RoundEvent
+	eventsCh            chan domain.RoundEvent
+	transactionEventsCh chan TransactionEvent
 
 	// cached data for the current round
 	lastEvent           domain.RoundEvent
@@ -62,16 +63,11 @@ func NewCovenantlessService(
 	builder ports.TxBuilder, scanner ports.BlockchainScanner,
 	scheduler ports.SchedulerService,
 ) (Service, error) {
-	eventsCh := make(chan domain.RoundEvent)
-	paymentRequests := newPaymentsMap()
-
-	forfeitTxs := newForfeitTxsMap(builder)
 	pubkey, err := walletSvc.GetPubkey(context.Background())
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch pubkey: %s", err)
 	}
 
-	sweeper := newSweeper(walletSvc, repoManager, builder, scheduler)
 	asyncPaymentsCache := make(map[string]struct {
 		receivers []domain.Receiver
 		expireAt  int64
@@ -87,10 +83,11 @@ func NewCovenantlessService(
 		repoManager:         repoManager,
 		builder:             builder,
 		scanner:             scanner,
-		sweeper:             sweeper,
-		paymentRequests:     paymentRequests,
-		forfeitTxs:          forfeitTxs,
-		eventsCh:            eventsCh,
+		sweeper:             newSweeper(walletSvc, repoManager, builder, scheduler),
+		paymentRequests:     newPaymentsMap(),
+		forfeitTxs:          newForfeitTxsMap(builder),
+		eventsCh:            make(chan domain.RoundEvent),
+		transactionEventsCh: make(chan TransactionEvent),
 		currentRoundLock:    sync.Mutex{},
 		asyncPaymentsCache:  asyncPaymentsCache,
 		treeSigningSessions: make(map[string]*musigSigningSession),
@@ -303,6 +300,14 @@ func (s *covenantlessService) CompleteAsyncPayment(
 
 	delete(s.asyncPaymentsCache, redeemTxid)
 
+	go func() {
+		s.transactionEventsCh <- RedeemTransactionEvent{
+			AsyncTxID:      redeemTxid,
+			SpentVtxos:     spentVtxos,
+			SpendableVtxos: vtxos,
+		}
+	}()
+
 	return nil
 }
 
@@ -579,6 +584,10 @@ func (s *covenantlessService) GetEventsChannel(ctx context.Context) <-chan domai
 	return s.eventsCh
 }
 
+func (s *covenantlessService) GetTransactionEventsChannel(ctx context.Context) <-chan TransactionEvent {
+	return s.transactionEventsCh
+}
+
 func (s *covenantlessService) GetRoundByTxid(ctx context.Context, roundTxid string) (*domain.Round, error) {
 	return s.repoManager.Rounds().GetRoundWithTxid(ctx, roundTxid)
 }
@@ -1262,7 +1271,27 @@ func (s *covenantlessService) updateVtxoSet(round *domain.Round) {
 				return
 			}
 		}()
+
 	}
+	go func() {
+		// nolint:all
+		tx, _ := psbt.NewFromRawBytes(strings.NewReader(round.UnsignedTx), true)
+		boardingInputs := make([]domain.VtxoKey, 0)
+		for i, in := range tx.Inputs {
+			if len(in.TaprootLeafScript) > 0 {
+				boardingInputs = append(boardingInputs, domain.VtxoKey{
+					Txid: tx.UnsignedTx.TxIn[i].PreviousOutPoint.Hash.String(),
+					VOut: tx.UnsignedTx.TxIn[i].PreviousOutPoint.Index,
+				})
+			}
+		}
+		s.transactionEventsCh <- RoundTransactionEvent{
+			RoundTxID:             round.Txid,
+			SpentVtxos:            getSpentVtxos(round.Payments),
+			SpendableVtxos:        s.getNewVtxos(round),
+			ClaimedBoardingInputs: boardingInputs,
+		}
+	}()
 }
 
 func (s *covenantlessService) propagateEvents(round *domain.Round) {