fix(ui): polish across routing, groups, inbounds, mobile sidebar

A bundle of small UI fixes that surfaced together while reviewing the
panel.

Routing rules — stale Edit after drag:
- Dragging a rule and then clicking its Edit button used to open the
  modal with the *previous* rule's content. Root cause: desktopColumns
  was memoized with [t, isMobile, rows.length] (rows.length doesn't
  change on reorder), so the cached render function kept handing AntD
  the openEdit closure that captured the pre-drag rules array. Fix is
  a rulesRef updated each render and read inside openEdit, so even the
  cached closure sees the live array.
- Mobile rule cards on the same page were hard to tell apart: bumped
  the inter-card gap, slightly stronger border, soft shadow, and a
  small centered divider line between adjacent cards.

Mobile drawer (dark / ultra):
- The AntD Menu inside the mobile drawer was rendering with its own
  darkItemBg (#15161a / #050507) while the drawer body used the
  lighter colorBgElevated, producing visible two-tone seams. Force
  the drawer-content / drawer-body to the same dark color that the
  desktop sider uses, and make the menus transparent so they inherit.

Row menus — visual grouping:
- Groups page row menu: moved Rename above the divider so the
  ordering reads safe → divider → destructive (Remove from group,
  Delete clients, Delete group only) instead of mixing the two
  groups.
- Inbounds page row menu: inserted a divider before delAllClients /
  delete so the destructive items sit visually separated from the
  earlier safe actions.

Dropdown affordances:
- Non-danger dropdown items had no perceivable hover state (default
  colorBgTextHover is too subtle, especially under the light theme).
  Apply the same primary-tint pattern the sider/drawer menu uses: 14%
  primary background and primary color on label + icon.
- ant-dropdown-menu-item-divider now uses var(--ant-color-border)
  (and an explicit rgba in dark) so the separator is actually visible
  in the light theme.

Clients toolbar — narrow-desktop wrap:
- Between 769px and 920px, the bulk-action bar (Attach / Detach /
  Add to group / Ungroup / more + Delete) wrapped to two rows with
  Delete stranded alone on the right. In that range, switch the
  toolbar buttons to icon-only, tighten gap to 6px and inline padding
  to 8px so everything stays on one line.

frontend/src/pages/groups/GroupsPage.tsx

@@ -332,6 +332,13 @@ export default function GroupsPage() {
         label: t('pages.groups.addToGroup'),
         onClick: () => openAddClientsFor(row),
       },
+      {
+        key: 'rename',
+        icon: <EditOutlined />,
+        label: t('pages.groups.rename'),
+        onClick: () => openRename(row),
+      },
+      { type: 'divider' },
       {
         key: 'removeClients',
         icon: <UsergroupDeleteOutlined />,
@@ -340,13 +347,6 @@ export default function GroupsPage() {
         disabled: !row.clientCount,
         onClick: () => openRemoveClientsFor(row),
       },
-      { type: 'divider' },
-      {
-        key: 'rename',
-        icon: <EditOutlined />,
-        label: t('pages.groups.rename'),
-        onClick: () => openRename(row),
-      },
       {
         key: 'deleteClients',
         icon: <DeleteOutlined />,