Show and extend the elevation window

A banner appears while elevated, counting down in minutes and carrying
extend and drop controls. Three extensions of 30 minutes are allowed, so
the window is at most two hours without a fresh code; a code resets the
budget. The countdown is advisory, the server-side check authoritative, so
it says "expired" rather than vanishing.

The post-login flash tells an admin the timer has started.

1 files changed, 1 insertions, 0 deletions

diff --git a/app/views/layouts/admin.html.erb b/app/views/layouts/admin.html.erb
index 43f09b96..a84c8927 100644
--- a/app/views/layouts/admin.html.erb
+++ b/app/views/layouts/admin.html.erb
@@ -43,6 +43,7 @@
         </div>
       </div>
       <div class="admin_content_spacer"></div>
+      <%= render "layouts/elevation_banner" %>
       <%= render "layouts/flash" %>
       <div id="content">
         <%= yield %>