docs(changeset): scope the objectui#11212 headline to what the diff publishes

The headline said the gated action stays hidden or disabled "on every
action surface". For `disabled` that overclaims: only `page:header`'s
disabled leg moved. The headline now names the `visible` surfaces and the
`page:header` `disabled` leg, which are the two the diff changes.

Claude-Session: https://claude.ai/code/session_0122Knsowci76D2rBWReCzzZ
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/11212-permission-gates-fail-closed.md

@@ -4,7 +4,7 @@
 '@object-ui/react': minor
 ---
 
-fix: an action gated on `current_user.can(object, verb)` stays hidden (or disabled) until the permissions payload has loaded, on every action surface, and `record:quick_actions` can answer `current_user` at all
+fix: an action gated on `current_user.can(object, verb)` stays hidden until the permissions payload has loaded on every action `visible` surface, a `page:header` action gated through `disabled` stays disabled, and `record:quick_actions` can answer `current_user` at all
 
 An action whose `visible` asks `current_user.can(...)` has no answer until the signed-in
 user's permissions have loaded. On `action:group` (both display modes, and the group's own