feat: add commission settlement endpoints

Tiku.Api/Middleware/ExceptionHandlingMiddleware.cs

@@ -215,6 +215,16 @@ public sealed class ExceptionHandlingMiddleware(
                 return;
             }
 
+            if (exception is CommissionException commissionException)
+            {
+                await WriteProblemAsync(
+                    context,
+                    commissionException.Message,
+                    CommissionStatusCode(commissionException.Code),
+                    commissionException.Code);
+                return;
+            }
+
             if (exception is PaymentProviderException paymentProviderException)
             {
                 await WriteProblemAsync(
@@ -410,4 +420,17 @@ public sealed class ExceptionHandlingMiddleware(
             _ => StatusCodes.Status400BadRequest
         };
     }
+
+    private static int CommissionStatusCode(string code)
+    {
+        return code switch
+        {
+            "commission_access_denied" => StatusCodes.Status403Forbidden,
+            "commission_member_not_found" or "commission_settlement_not_found" or "commission_proof_not_found" =>
+                StatusCodes.Status404NotFound,
+            "commission_no_unsettled_sources" or "commission_below_minimum" or "commission_status_invalid" or
+                "commission_proof_closed" => StatusCodes.Status409Conflict,
+            _ => StatusCodes.Status400BadRequest
+        };
+    }
 }