Decouple workflow services from HTTP result types

Endpoints/EndpointHelpers.cs

@@ -112,6 +112,22 @@ internal static class EndpointHelpers
 
     public static IResult UnauthorizedError(string detail = "Unauthorized") => Problem(StatusCodes.Status401Unauthorized, "Unauthorized", detail);
 
+    public static IResult ToHttpResult<T>(this ServiceResult<T> result, Func<T, IResult> onSuccess)
+    {
+        if (result.IsSuccess)
+            return onSuccess(result.Value!);
+
+        return ToHttpError(result.Error!);
+    }
+
+    public static IResult ToHttpResult(this ServiceResult<Unit> result, Func<IResult> onSuccess)
+    {
+        if (result.IsSuccess)
+            return onSuccess();
+
+        return ToHttpError(result.Error!);
+    }
+
     public static bool IsSqliteConstraintViolation(DbUpdateException ex)
     {
         return ex.InnerException is SqliteException sqliteEx
@@ -160,6 +176,18 @@ internal static class EndpointHelpers
             || path.EndsWith(".avif", StringComparison.Ordinal);
     }
 
+    private static IResult ToHttpError(ServiceError error)
+    {
+        return error.Code switch
+        {
+            ServiceErrorCode.BadRequest => BadRequestError(error.Detail),
+            ServiceErrorCode.Unauthorized => UnauthorizedError(error.Detail),
+            ServiceErrorCode.NotFound => NotFoundError(error.Detail),
+            ServiceErrorCode.Conflict => ConflictError(error.Detail),
+            _ => Problem(StatusCodes.Status500InternalServerError, "Internal Server Error", "Unhandled service error.")
+        };
+    }
+
     public static HttpMessageHandler CreateImageValidationHandler()
     {
         return new SocketsHttpHandler