"New Broadcast" no longer pinned to the top of the broadcast list

[cwillisf]

The "New Broadcast" entry is no longer pinned to the top of the broadcast dropdown. Repro confirmed by @kaylen-s (2026-05-05).

• https://scratch.mit.edu/discuss/topic/878547/

[VIUK-XV]

@cwillisf I'd like to work on this regression. My plan is to first add a failing test that confirms "New Broadcast" remains pinned to the top, then make the smallest scoped fix. Could you assign this issue to me and add a priority label if it is appropriate for an external PR?

For transparency, I will use AI assistance for code exploration and review, while personally validating, understanding, and explaining every submitted change.