feat: section preprod (env prod/preprod) + intégration ANTS (prod+preprod, jeu web)

- servers groupés par environnement (Production / Preprod) avec en-têtes
- ANTS prod (ants-web) + preprod (ants-web-rd) intégrés : jeu web, bouton Ouvrir
- The Cycle preprod (the-cycle-api-rd) ajouté
- badge PREPROD sur les cartes concernées, thème ANTS (fourmi/ambre)
- supprime le widget_test.dart par défaut (cassé, non compilé dans l'APK)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/screens/servers_screen.dart

@@ -130,13 +130,29 @@ class _ServersScreenState extends State<ServersScreen> {
     if (_servers == null) {
       return const Center(child: CircularProgressIndicator());
     }
-    return ListView.separated(
-      padding: const EdgeInsets.fromLTRB(16, 8, 16, 24),
-      itemCount: _servers!.length,
-      separatorBuilder: (_, __) => const SizedBox(height: 14),
-      itemBuilder: (_, i) {
-        final s = _servers![i];
-        return FutureBuilder<String>(
+
+    final prod = _servers!.where((s) => !s.isPreprod).toList();
+    final preprod = _servers!.where((s) => s.isPreprod).toList();
+
+    final children = <Widget>[];
+    if (prod.isNotEmpty) {
+      children.add(const _SectionHeader(label: 'Production', icon: Icons.public));
+      children.addAll(prod.map(_card));
+    }
+    if (preprod.isNotEmpty) {
+      children.add(const _SectionHeader(label: 'Preprod', icon: Icons.science_outlined));
+      children.addAll(preprod.map(_card));
+    }
+
+    return ListView(
+      padding: const EdgeInsets.fromLTRB(16, 4, 16, 24),
+      children: children,
+    );
+  }
+
+  Widget _card(GameServer s) => Padding(
+        padding: const EdgeInsets.only(bottom: 14),
+        child: FutureBuilder<String>(
           future: widget.api.iconUrl(s.id),
           builder: (_, snap) => ServerCard(
             server: s,
@@ -144,8 +160,29 @@ class _ServersScreenState extends State<ServersScreen> {
             busy: _busy.contains(s.id),
             onToggle: () => _toggle(s),
           ),
-        );
-      },
+        ),
+      );
+}
+
+class _SectionHeader extends StatelessWidget {
+  const _SectionHeader({required this.label, required this.icon});
+  final String label;
+  final IconData icon;
+
+  @override
+  Widget build(BuildContext context) {
+    final c = Theme.of(context).colorScheme.onSurfaceVariant;
+    return Padding(
+      padding: const EdgeInsets.fromLTRB(4, 14, 4, 10),
+      child: Row(
+        children: [
+          Icon(icon, size: 18, color: c),
+          const SizedBox(width: 8),
+          Text(label.toUpperCase(),
+              style: TextStyle(
+                  color: c, fontSize: 13, fontWeight: FontWeight.w800, letterSpacing: 1.1)),
+        ],
+      ),
     );
   }
 }