feat: isolate manual verification RPC usage

- add rpc node purpose support for general/manual_verify/both
- keep scan, WSS and health checks away from manual_verify nodes
- fallback manual hash verification from general RPC to manual_verify RPC
- add public cashier hash submission path and errno responses
- update tests for RPC selection, failover and manual payment flows

src/util/http/response_test.go

@@ -0,0 +1,61 @@
+package http
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	nethttp "net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/GMWalletApp/epusdt/util/constant"
+	"github.com/labstack/echo/v4"
+)
+
+func TestFailJsonHidesPlainErrorsBehindSystemErrno(t *testing.T) {
+	e := echo.New()
+	req := httptest.NewRequest(nethttp.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+	ctx := e.NewContext(req, rec)
+
+	if err := new(Resp).FailJson(ctx, errors.New("database connection details")); err != nil {
+		t.Fatalf("FailJson returned error: %v", err)
+	}
+	if rec.Code != nethttp.StatusBadRequest {
+		t.Fatalf("http status = %d, want 400", rec.Code)
+	}
+
+	var body map[string]interface{}
+	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
+		t.Fatalf("unmarshal response: %v", err)
+	}
+	if got := int(body["status_code"].(float64)); got != 400 {
+		t.Fatalf("status_code = %d, want 400; body=%v", got, body)
+	}
+	if got, _ := body["message"].(string); got != constant.Errno[400] {
+		t.Fatalf("message = %q, want %q", got, constant.Errno[400])
+	}
+}
+
+func TestFailJsonPreservesWrappedRspErrorErrno(t *testing.T) {
+	e := echo.New()
+	req := httptest.NewRequest(nethttp.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+	ctx := e.NewContext(req, rec)
+
+	err := fmt.Errorf("wrap: %w", constant.OrderNotExists)
+	if callErr := new(Resp).FailJson(ctx, err); callErr != nil {
+		t.Fatalf("FailJson returned error: %v", callErr)
+	}
+
+	var body map[string]interface{}
+	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
+		t.Fatalf("unmarshal response: %v", err)
+	}
+	if got := int(body["status_code"].(float64)); got != 10008 {
+		t.Fatalf("status_code = %d, want 10008; body=%v", got, body)
+	}
+	if got, _ := body["message"].(string); got != constant.Errno[10008] {
+		t.Fatalf("message = %q, want %q", got, constant.Errno[10008])
+	}
+}