Add wallet service implementation and mock CLI tool

- pkg/protocol/nwc/wallet.go
  - Implemented `WalletService` with method registration and request handling.
  - Added default stub handlers for supported wallet methods.
  - Included support for notifications with `SendNotification`.

- pkg/protocol/nwc/client-methods.go
  - Added `Subscribe` function for handling client subscriptions.

- cmd/walletcli/mock-wallet-service/main.go
  - Implemented a mock CLI tool for wallet service.
  - Added command-line flags for relay connection and key management.
  - Added handlers for various wallet service methods (e.g., `GetInfo`, `GetBalance`, etc.).

- pkg/protocol/nwc/types.go
  - Added `GetWalletServiceInfo` to the list of wallet service capabilities.

pkg/protocol/nwc/wallet-methods.go

@@ -0,0 +1,182 @@
+package nwc
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"orly.dev/pkg/utils/context"
+)
+
+// handleGetWalletServiceInfo handles the GetWalletServiceInfo method.
+func (ws *WalletService) handleGetWalletServiceInfo(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Empty stub implementation
+	return &WalletServiceInfo{}, nil
+}
+
+// handleCancelHoldInvoice handles the CancelHoldInvoice method.
+func (ws *WalletService) handleCancelHoldInvoice(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p CancelHoldInvoiceParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return nil, nil
+}
+
+// handleCreateConnection handles the CreateConnection method.
+func (ws *WalletService) handleCreateConnection(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p CreateConnectionParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return nil, nil
+}
+
+// handleGetBalance handles the GetBalance method.
+func (ws *WalletService) handleGetBalance(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Empty stub implementation
+	return &GetBalanceResult{}, nil
+}
+
+// handleGetBudget handles the GetBudget method.
+func (ws *WalletService) handleGetBudget(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Empty stub implementation
+	return &GetBudgetResult{}, nil
+}
+
+// handleGetInfo handles the GetInfo method.
+func (ws *WalletService) handleGetInfo(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Empty stub implementation
+	return &GetInfoResult{}, nil
+}
+
+// handleListTransactions handles the ListTransactions method.
+func (ws *WalletService) handleListTransactions(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p ListTransactionsParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &ListTransactionsResult{}, nil
+}
+
+// handleLookupInvoice handles the LookupInvoice method.
+func (ws *WalletService) handleLookupInvoice(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p LookupInvoiceParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &LookupInvoiceResult{}, nil
+}
+
+// handleMakeHoldInvoice handles the MakeHoldInvoice method.
+func (ws *WalletService) handleMakeHoldInvoice(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p MakeHoldInvoiceParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &MakeInvoiceResult{}, nil
+}
+
+// handleMakeInvoice handles the MakeInvoice method.
+func (ws *WalletService) handleMakeInvoice(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p MakeInvoiceParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &MakeInvoiceResult{}, nil
+}
+
+// handlePayKeysend handles the PayKeysend method.
+func (ws *WalletService) handlePayKeysend(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p PayKeysendParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &PayKeysendResult{}, nil
+}
+
+// handlePayInvoice handles the PayInvoice method.
+func (ws *WalletService) handlePayInvoice(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p PayInvoiceParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &PayInvoiceResult{}, nil
+}
+
+// handleSettleHoldInvoice handles the SettleHoldInvoice method.
+func (ws *WalletService) handleSettleHoldInvoice(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p SettleHoldInvoiceParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return nil, nil
+}
+
+// handleSignMessage handles the SignMessage method.
+func (ws *WalletService) handleSignMessage(c context.T, params json.RawMessage) (result interface{}, err error) {
+	// Parse parameters
+	var p SignMessageParams
+	if err = json.Unmarshal(params, &p); err != nil {
+		return nil, &ResponseError{
+			Code:    "invalid_params",
+			Message: fmt.Sprintf("failed to parse parameters: %v", err),
+		}
+	}
+
+	// Empty stub implementation
+	return &SignMessageResult{}, nil
+}