Sidebar does not show a newly created session immediately

[Raymond8196]

Problem

After creating a top-level native session, the session can exist in the local entity cache but remain absent from the sidebar until a later roster refresh. The sidebar filters rows by its paginated roster after the first page has loaded, and the creation path did not register the new session ID there.

An in-flight first-page request can also return after creation and overwrite a local registration with an older response.

Steps to reproduce

1. Open the Workstation sidebar so its session roster has loaded.
2. Create a new top-level native session.
3. Observe the sidebar while the first turn is still running.

Expected behavior

The new session appears in the sidebar immediately after the launch response succeeds and remains visible if an older roster request finishes afterward. Child and imported sessions must remain outside the primary native roster.

Scope

• Register newly created primary native sessions at the entity-store write boundary.
• Preserve registrations made after a roster read begins when that read commits.
• Add regressions for both the already-loaded roster and stale-first-page orderings.