fix: remove incorrect cents-to-dollars conversion in notification currency display

ROOT_CAUSE_ANALYSIS.md

@@ -0,0 +1,61 @@
+# Root Cause Analysis: Notification Currency Display Bug
+
+## Bug Summary
+
+Order confirmation notification emails display incorrect monetary amounts. A $149.99 order shows as $1.50 in the email preview.
+
+## Root Cause
+
+The `FormatCurrency` method in `NotificationRenderer.cs` divides the amount by 100, assuming the input value is in **cents** (integer representation):
+
+```csharp
+private static string FormatCurrency(decimal amount)
+{
+    // The OrderPlacedEvent.TotalAmount is transmitted in cents (integer
+    // representation) to avoid floating-point precision issues across
+    // service boundaries. Convert back to dollars for display.
+    var dollars = amount / 100m;
+    return dollars.ToString("C2");
+}
+```
+
+However, the `OrderPlacedEvent` contract defines `TotalAmount` as a `decimal` representing **dollars**, not cents:
+
+```csharp
+public record OrderPlacedEvent(
+    Guid OrderId,
+    Guid CustomerId,
+    decimal TotalAmount,  // Already in dollars (e.g., 149.99)
+    DateTime PlacedAt
+);
+```
+
+The division `149.99 / 100 = 1.4999` then formats to `$1.50`, which is off by a factor of 100.
+
+## Why It Happened
+
+The misleading comment in `FormatCurrency` claimed the amount was "transmitted in cents" but neither the shared contract (`OrderPlacedEvent`), the HTTP DTO (`OrderPlacedEventDto`), nor the domain entity (`OrderNotification.OrderTotal`) treat the value as cents. The entire data pipeline passes the amount as a dollar-denominated decimal. The `/100m` division was incorrect from the start.
+
+## Fix
+
+Removed the erroneous `/100m` division so the amount formats directly:
+
+```csharp
+private static string FormatCurrency(decimal amount)
+{
+    return amount.ToString("C2");
+}
+```
+
+## Files Changed
+
+| File | Change |
+|------|--------|
+| `src/Services/Notification/Notification.API/Services/NotificationRenderer.cs` | Removed `/100m` division in `FormatCurrency` |
+| `src/Services/Notification/Notification.API/Notification.API.csproj` | Fixed project reference paths to `Shared.*` projects |
+| `src/global.json` | Updated SDK version to match installed .NET 10 RC |
+
+## Verification
+
+- **Before fix**: POST `totalAmount: 149.99` -> email preview shows $1.50
+- **After fix**: POST `totalAmount: 149.99` -> email preview shows $149.99

src/Services/Notification/Notification.API/Notification.API.csproj

@@ -7,8 +7,8 @@
   <ItemGroup>
     <ProjectReference Include="..\Notification.Domain\Notification.Domain.csproj" />
     <ProjectReference Include="..\Notification.Infrastructure\Notification.Infrastructure.csproj" />
-    <ProjectReference Include="..\..\Shared\Shared.Contracts\Shared.Contracts.csproj" />
-    <ProjectReference Include="..\..\Shared\Shared.Infrastructure\Shared.Infrastructure.csproj" />
+    <ProjectReference Include="..\..\..\Shared\Shared.Contracts\Shared.Contracts.csproj" />
+    <ProjectReference Include="..\..\..\Shared\Shared.Infrastructure\Shared.Infrastructure.csproj" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="10.*" />

src/Services/Notification/Notification.API/Services/NotificationRenderer.cs

@@ -11,16 +11,11 @@ public class NotificationRenderer
 {
     /// <summary>
     /// Formats a monetary amount for display in notification emails.
-    /// Converts the raw amount from the OrderPlacedEvent into a
-    /// user-friendly currency string.
+    /// The amount is already in dollars (decimal), so no conversion needed.
     /// </summary>
     private static string FormatCurrency(decimal amount)
     {
-        // The OrderPlacedEvent.TotalAmount is transmitted in cents (integer
-        // representation) to avoid floating-point precision issues across
-        // service boundaries. Convert back to dollars for display.
-        var dollars = amount / 100m;
-        return dollars.ToString("C2");
+        return amount.ToString("C2");
     }
 
     public string RenderOrderConfirmation(OrderNotification notification)

src/global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "10.0.100",
-    "rollForward": "latestFeature"
+    "version": "10.0.100-rc.2.25502.107",
+    "rollForward": "latestMajor"
   }
 }