feat(shell): real sprout logo on home + basic Settings screen

- Bundle the real sprout logo (docs/logo.png → assets/logo.png) and show it on
  the home menu instead of a Material icon.
- Settings screen: switch language (Español / English / system) via slang, plus
  an About tile (logo, app name, one-line description). Drawer "Settings" is now
  active and routes to /settings.

Tests: drawer Settings opens the screen and shows the language options. 54 green.

apps/app_seeds/lib/ui/app_drawer.dart

@@ -38,7 +38,14 @@ class AppDrawer extends StatelessWidget {
             _SoonItem(icon: Icons.group_outlined, label: t.menu.following),
             const Spacer(),
             const Divider(),
-            _SoonItem(icon: Icons.settings_outlined, label: t.menu.settings),
+            _ActiveItem(
+              icon: const Icon(Icons.settings_outlined),
+              label: t.menu.settings,
+              onTap: () {
+                Navigator.of(context).pop();
+                context.go('/settings');
+              },
+            ),
           ],
         ),
       ),