Clean up Groups tab heading, add spacing under Administration subtitle (v0.16.15)

ROADMAP.md

@@ -154,3 +154,5 @@ Roughly in priority order:
 `v0.16.13` fixes three Administration/Logs layout inconsistencies found in live use. First, the Groups tab was missing the stat-count bar ("N Administrators · N Standard Users · ...") that every other listing tab (Users) shows, making it look unfinished by comparison — added a matching Enabled/Disabled group count bar. Second, "Create group" lived in its own row inside the Groups panel instead of the shared top-right header button used by "Create user," "New hosted site," and every other creation action — moved it into that same header slot so it behaves and aligns like all the others. Third, the Logs page's "Refresh logs" button (and Performance's and Certificates') sat directly against the first box below it with no gap, because those three pages are the only ones with no status-summary bar to provide the usual spacing under the page header — added a matching top margin so they're consistent with every other page.
 
 `v0.16.14` fixes the Create button (Create user / Create group) disappearing or showing the wrong label after switching Administration tabs. Root cause: a leftover click handler on the admin tabs bar, written before Groups had a Create button at all, still hard-coded "hide the shared Create button unless the tab is Users" and manually poked tab-active/panel-visibility classes directly -- completely independent of and out of sync with the real logic added in v0.16.13's `render()`. Since that same handler also fires when the app restores your last-viewed tab on page load/refresh, it would immediately stomp the button back to the wrong state. Replaced both old handlers with one that simply updates state and calls the real `render()`, so there's a single source of truth for tab switching instead of two handlers disagreeing with each other.
+
+`v0.16.15` cleans up the Groups tab's layout: removed the redundant "Groups / Organize users for Access List permissions." heading, since the tab button and admin panel description already say what the tab is, and it was adding a bare, boxless line of text found nowhere else in Administration once the tab's own Create button moved to the shared header. The Enabled/Disabled stat bar is now the first thing in the panel, structurally matching how the Users tab's own stat bar is positioned. Also added top spacing between the Administration page's subtitle and the row of tab buttons (System, Users, Groups, ...) below it -- that gap had never been set, so the tabs bar sat flush against the subtitle text.