CreateBookmarkArgs does not expose Payload as shown in documentation

### Description

While following the official documentation for creating a blocking activity:

* Docs:
* Referenced example:

I encountered a mismatch between the documented API and the actual implementation.

The documentation and sample code reference a `Payload` property on `CreateBookmarkArgs`, but this property does not appear to exist in the current version of the library.

### Code from documentation

```csharp
var bookmarkArgs = new CreateBookmarkArgs
{
BookmarkName = "WaitForApproval",
Payload = new Dictionary
{
["ApprovalMessage"] = message ?? string.Empty,
["ActivityInstanceId"] = context.ActivityExecutionContext.Id
},
Callback = OnResumeAsync,
AutoBurn = true
};
```

### Observed behavior

* `CreateBookmarkArgs` does **not** contain a `Payload` property.
* IntelliSense and inspection confirm that this property is not present.

### Expected behavior

Documentation should be updated to reflect the correct way of passing correlation data / bookmark payload in the current API.

### Additional context

When inspecting `CreateBookmarkArgs`, I don’t see any obvious alternative for setting payload or correlation data for bookmark hashing.

### Questions

* Has `Payload` been removed or renamed in a newer version?
* What is the correct way to provide bookmark correlation data now?
* Is there an updated example for `WaitForApprovalActivity` compatible with the current version?

Start with the documented WaitForApprovalActivity.cs example and inspect the current CreateBookmarkArgs API to determine how correlation data is represented now. Update the blocking-and-triggers documentation and example to use the current API, with the example compiling against the current library and explaining the supported payload or correlation approach.

Written by the indexing model from the issue text.