bookmark: attach updated payload when current bookmark matches updated bookmark

In `packages/modules/bookmark/src/BookmarkProvider.ts`, the bookmark update success handler has:

```ts
map(
// TODO: add payload if current bookmark is the same as the updated bookmark
({ payload }): Bookmark =>
({
...bookmarkSelector(this.#store.value, payload.id),
payload: payload.payload,
}) as Bookmark,
),
```

Investigate merging/attaching the updated `payload` onto the current bookmark when the updated bookmark is the currently active one, so consumers observing the current bookmark get the fresh payload data immediately.

Read packages/modules/bookmark/src/BookmarkProvider.ts, starting with the bookmark update success handler and bookmarkSelector usage. Trace how the current bookmark is identified and how consumers observe it, then verify that the active bookmark receives the updated payload immediately without changing unrelated bookmarks.

Written by the indexing model from the issue text.