feat(pos-transactions-bff): align lifecycle transaction detail

docs/api/pos-transaction-workflows.md

@@ -21,10 +21,11 @@ This BFF exposes POS summary, transaction detail, recent payment activity, and p
 - Default runtime target: `http://operations-service:8080`
 - Internal upstream routes:
   - `GET /internal/operations/pos/summary`
+  - `GET /internal/operations/pos/transactions/{transactionId}`
   - `POST /internal/operations/pos/payments`
 
 ## Notes
 
 - POS summary and detail are derived from payable restaurant checks exposed by `operations-service`, not from an independent payment event store.
-- Transaction detail is currently derived from the payable-check snapshot returned by `operations-service`.
+- Transaction detail now comes from a dedicated lifecycle-backed upstream route instead of being projected from the summary snapshot.
 - Correlation IDs are preserved through Thalos session checks and operations-service calls.

src/Pos.Transactions.Bff.Application/Adapters/OperationsPosTransactionsServiceClient.cs

@@ -21,18 +21,14 @@ public sealed class OperationsPosTransactionsServiceClient(HttpClient httpClient
 
     public async Task<GetPosTransactionDetailResponse> FetchDetailAsync(GetPosTransactionDetailRequest request, CancellationToken cancellationToken)
     {
-        var payload = await GetSummaryPayloadAsync(request.ContextId, cancellationToken);
+        var payload = await GetDetailPayloadAsync(request.ContextId, request.TransactionId, cancellationToken);
-        // POS detail remains a projection over the payable-check summary until operations-service exposes a dedicated detail route.
-        var payment = MapPayments(payload.RecentPayments).FirstOrDefault(activity => activity.TransactionId == request.TransactionId);
 
         return new GetPosTransactionDetailResponse(
             payload.ContextId,
-            payment is null
+            payload.Summary,
-                ? $"Transaction {request.TransactionId} is not visible in the current POS summary."
-                : $"Transaction {request.TransactionId} is currently {payment.Status}.",
             payload.OpenBalance,
             payload.Currency,
-            payment);
+            payload.Transaction is null ? null : MapPayment(payload.Transaction));
     }
 
     public async Task<GetRecentPosPaymentsResponse> FetchRecentPaymentsAsync(GetPosTransactionSummaryRequest request, CancellationToken cancellationToken)
@@ -69,6 +65,18 @@ public sealed class OperationsPosTransactionsServiceClient(HttpClient httpClient
         return payload ?? throw new InvalidOperationException("Operations service returned an empty POS summary payload.");
     }
 
+    private async Task<GetPosTransactionDetailPayload> GetDetailPayloadAsync(
+        string contextId,
+        string transactionId,
+        CancellationToken cancellationToken)
+    {
+        var payload = await httpClient.GetFromJsonAsync<GetPosTransactionDetailPayload>(
+            $"internal/operations/pos/transactions/{Uri.EscapeDataString(transactionId)}?contextId={Uri.EscapeDataString(contextId)}",
+            cancellationToken);
+
+        return payload ?? throw new InvalidOperationException("Operations service returned an empty POS detail payload.");
+    }
+
     private async Task<CapturePosPaymentResponsePayload> CapturePaymentPayloadAsync(
         CapturePosPaymentRequest request,
         CancellationToken cancellationToken)
@@ -83,14 +91,19 @@ public sealed class OperationsPosTransactionsServiceClient(HttpClient httpClient
     private static IReadOnlyCollection<PosPaymentActivityContract> MapPayments(IReadOnlyCollection<PosPaymentActivityPayload> payments)
     {
         return payments
-            .Select(static payment => new PosPaymentActivityContract(
+            .Select(MapPayment)
+            .ToArray();
+    }
+
+    private static PosPaymentActivityContract MapPayment(PosPaymentActivityPayload payment)
+    {
+        return new PosPaymentActivityContract(
             payment.TransactionId,
             payment.PaymentMethod,
             payment.Amount,
             payment.Currency,
             payment.Status,
-                payment.CapturedAtUtc))
+            payment.CapturedAtUtc);
-            .ToArray();
     }
 
     private sealed record GetPosTransactionSummaryPayload(
@@ -108,6 +121,13 @@ public sealed class OperationsPosTransactionsServiceClient(HttpClient httpClient
         string Status,
         DateTime CapturedAtUtc);
 
+    private sealed record GetPosTransactionDetailPayload(
+        string ContextId,
+        string Summary,
+        decimal OpenBalance,
+        string Currency,
+        PosPaymentActivityPayload? Transaction);
+
     private sealed record CapturePosPaymentResponsePayload(
         string ContextId,
         string TransactionId,

tests/Pos.Transactions.Bff.Application.UnitTests/OperationsPosTransactionsServiceClientTests.cs

@@ -10,7 +10,10 @@ public sealed class OperationsPosTransactionsServiceClientTests
     [Fact]
     public async Task FetchSummaryAsync_MapsBalanceCurrencyAndPayments()
     {
-        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(SummaryPayload));
+        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(new Dictionary<string, string>
+        {
+            ["/internal/operations/pos/summary"] = SummaryPayload
+        }));
 
         var response = await adapter.FetchSummaryAsync(new GetPosTransactionSummaryRequest("demo-context"), CancellationToken.None);
 
@@ -22,7 +25,10 @@ public sealed class OperationsPosTransactionsServiceClientTests
     [Fact]
     public async Task FetchDetailAsync_ReturnsMatchingTransactionWhenPresent()
     {
-        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(SummaryPayload));
+        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(new Dictionary<string, string>
+        {
+            ["/internal/operations/pos/transactions/CHK-1002"] = DetailPayload
+        }));
 
         var response = await adapter.FetchDetailAsync(new GetPosTransactionDetailRequest("demo-context", "CHK-1002"), CancellationToken.None);
 
@@ -34,7 +40,10 @@ public sealed class OperationsPosTransactionsServiceClientTests
     [Fact]
     public async Task FetchRecentPaymentsAsync_ReturnsProjectedPaymentHistory()
     {
-        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(SummaryPayload));
+        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(new Dictionary<string, string>
+        {
+            ["/internal/operations/pos/summary"] = SummaryPayload
+        }));
 
         var response = await adapter.FetchRecentPaymentsAsync(new GetPosTransactionSummaryRequest("demo-context"), CancellationToken.None);
 
@@ -44,7 +53,9 @@ public sealed class OperationsPosTransactionsServiceClientTests
     [Fact]
     public async Task CapturePaymentAsync_MapsCaptureWorkflowPayload()
     {
-        var adapter = new OperationsPosTransactionsServiceClient(CreateClient("""
+        var adapter = new OperationsPosTransactionsServiceClient(CreateClient(new Dictionary<string, string>
+        {
+            ["/internal/operations/pos/payments"] = """
             {
               "contextId": "demo-context",
               "transactionId": "POS-9003",
@@ -53,7 +64,8 @@ public sealed class OperationsPosTransactionsServiceClientTests
               "status": "captured",
               "capturedAtUtc": "2026-03-31T14:05:00Z"
             }
-            """));
+            """
+        }));
 
         var response = await adapter.CapturePaymentAsync(
             new CapturePosPaymentRequest("demo-context", "POS-9003", 19.95m, "USD", "card"),
@@ -63,18 +75,24 @@ public sealed class OperationsPosTransactionsServiceClientTests
         Assert.Equal("captured", response.Status);
     }
 
-    private static HttpClient CreateClient(string json)
+    private static HttpClient CreateClient(IReadOnlyDictionary<string, string> routes)
     {
-        return new HttpClient(new StubHttpMessageHandler(json))
+        return new HttpClient(new StubHttpMessageHandler(routes))
         {
             BaseAddress = new Uri("http://operations-service:8080/")
         };
     }
 
-    private sealed class StubHttpMessageHandler(string json) : HttpMessageHandler
+    private sealed class StubHttpMessageHandler(IReadOnlyDictionary<string, string> routes) : HttpMessageHandler
     {
         protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         {
+            var path = request.RequestUri?.AbsolutePath ?? string.Empty;
+            if (!routes.TryGetValue(path, out var json))
+            {
+                throw new InvalidOperationException($"No stub payload configured for '{path}'.");
+            }
+
             return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
             {
                 Content = new StringContent(json, Encoding.UTF8, "application/json")
@@ -108,4 +126,21 @@ public sealed class OperationsPosTransactionsServiceClientTests
           ]
         }
         """;
+
+    private const string DetailPayload = """
+        {
+          "contextId": "demo-context",
+          "summary": "Transaction CHK-1002 maps to check CHK-1002 and is currently awaiting-payment.",
+          "openBalance": 37.50,
+          "currency": "USD",
+          "transaction": {
+            "transactionId": "CHK-1002",
+            "paymentMethod": "check",
+            "amount": 25.50,
+            "currency": "USD",
+            "status": "awaiting-payment",
+            "capturedAtUtc": "2026-03-31T13:30:00Z"
+          }
+        }
+        """;
 }