fix(nav): inventory is a spoke off the home hub — back arrow, no duplicate drawer

The inventory screen carried its own const AppDrawer() (no marketEnabled),
so opening the menu from inventory greyed out market/chat/profile — the
recurring 'phase 1' look. It was also reached via go() (route replace),
which is why it showed a hamburger instead of a back arrow like the market.

Make it coherent with the market: reach inventory via push() (from the
home card and the drawer), and drop its drawer so the AppBar shows a back
arrow returning to the home hub. The drawer now lives only on the home
screen, which always passes marketEnabled — the wrong-drawer bug class is
gone. Update the home_screen test to assert the spoke has a back arrow and
no hamburger.

apps/app_seeds/lib/ui/app_drawer.dart

@@ -31,7 +31,7 @@ class AppDrawer extends StatelessWidget {
               label: t.menu.inventory,
               onTap: () {
                 Navigator.of(context).pop();
-                context.go('/inventory');
+                context.push('/inventory');
               },
             ),
             _DrawerItem(