React Navigation keeps a screen's descriptor, and with it the native
header, while the screen's options stay shallowly equal.
NativeStackScreenOptions keeps each option function's identity stable
and re-applies the options when what those functions return changes,
so the re-application never reached the header. A toolbar that gained
an action, or a menu whose action changed, kept showing the old one.
On the iPhone Duo, unfolding and folding again left the thread list
without Compose.

A re-application now hands the header new function wrappers. The
toolbar test's navigation mock skips options that stay shallowly
equal, as React Navigation does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>