[AC-1943] Implement provider client invoice report (#4178)

* Update ProviderInvoiceItem SQL configuration

* Implement provider client invoice export

* Add tests

* Run dotnet format

* Fixed SPROC backwards compatibility issue

src/Api/Billing/Controllers/ProviderBillingController.cs

@@ -42,6 +42,28 @@ public class ProviderBillingController(
         return TypedResults.Ok(response);
     }
 
+    [HttpGet("invoices/{invoiceId}")]
+    public async Task<IResult> GenerateClientInvoiceReportAsync([FromRoute] Guid providerId, string invoiceId)
+    {
+        var (provider, result) = await GetAuthorizedBillableProviderOrResultAsync(providerId);
+
+        if (provider == null)
+        {
+            return result;
+        }
+
+        var reportContent = await providerBillingService.GenerateClientInvoiceReport(invoiceId);
+
+        if (reportContent == null)
+        {
+            return TypedResults.NotFound();
+        }
+
+        return TypedResults.File(
+            reportContent,
+            "text/csv");
+    }
+
     [HttpGet("payment-information")]
     public async Task<IResult> GetPaymentInformationAsync([FromRoute] Guid providerId)
     {

src/Api/Billing/Models/Responses/InvoicesResponse.cs

@@ -13,6 +13,7 @@ public record InvoicesResponse(
 }
 
 public record InvoiceDTO(
+    string Id,
     DateTime Date,
     string Number,
     decimal Total,
@@ -21,6 +22,7 @@ public record InvoiceDTO(
     string PdfUrl)
 {
     public static InvoiceDTO From(Invoice invoice) => new(
+        invoice.Id,
         invoice.Created,
         invoice.Number,
         invoice.Total / 100M,