Add menu enable toggle, user status, and mobile/UI polish

- Admin menu page: mobile item cards now put Actions in the top-right
  corner next to Status, matching the desktop row layout instead of
  stacking at the bottom; same treatment applied to announcements and
  users for consistency across all three admin lists
- Center button label text everywhere via .btn { justify-content: center }
  instead of one-off overrides
- Add a Disable/Enable Menu toggle to the admin menu toolbar; the public
  menu page shows its existing "menu being updated" message while disabled
- Add an Enabled/Disabled status to user accounts, with its own toggle
  badge, guardrails against disabling your own account or the last
  enabled account, and an immediate session kick for anyone disabled
  mid-session
- Fix the announcement banner / hero tagline "·" separators to hide only
  when their neighboring text actually wraps onto a different line,
  instead of a fixed breakpoint or always-on dot

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

admin/index.php

@@ -215,14 +215,16 @@ $announcements = get_all_announcements();
                   </div>
                   <div data-label="Actions">
                     <div class="row-actions">
-                      <a href="index.php?edit=<?= (int)$ann['id'] ?>" class="btn btn-outline btn-sm">Edit</a>
+                      <div class="action-stack">
+                        <a href="index.php?edit=<?= (int)$ann['id'] ?>" class="btn btn-outline btn-sm">Edit</a>
 
-                      <form method="POST" action="index.php" style="display: inline;" onsubmit="return confirm('Are you sure you want to delete this announcement?');">
-                        <input type="hidden" name="action" value="delete_announcement">
-                        <input type="hidden" name="csrf_token" value="<?= htmlspecialchars(get_csrf_token()) ?>">
-                        <input type="hidden" name="announcement_id" value="<?= (int)$ann['id'] ?>">
-                        <button type="submit" class="btn btn-danger btn-sm">Delete</button>
-                      </form>
+                        <form method="POST" action="index.php" style="display: inline;" onsubmit="return confirm('Are you sure you want to delete this announcement?');">
+                          <input type="hidden" name="action" value="delete_announcement">
+                          <input type="hidden" name="csrf_token" value="<?= htmlspecialchars(get_csrf_token()) ?>">
+                          <input type="hidden" name="announcement_id" value="<?= (int)$ann['id'] ?>">
+                          <button type="submit" class="btn btn-danger btn-sm">Delete</button>
+                        </form>
+                      </div>
                     </div>
                   </div>
                 </div>