Tab Community, tombol Bayar di navbar, logo placeholder, fix crash PIN

- Bottom navbar: Home, Pesanan, Bayar (tombol tengah ke kode bayar),
  Community, Profil; menu EnakCommunity di beranda pindah ke tab
- Image placeholder: logo Enaklo diperbesar, ilustrasi gelas dihapus
- Fix assertion Navigator saat PIN gagal karena error non-PIN: flushbar
  kini tampil lewat onFailure setelah sheet PIN tertutup (bayar, tukar,
  transfer)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/presentation/pages/main/main_page.dart

@@ -21,6 +21,14 @@ class _MainPageState extends State<MainPage> {
     context.read<AuthBloc>().add(const AuthEvent.fetchCurrentUser());
   }
 
+  /// Kode bayar di kasir; PIN diminta di halamannya sendiri.
+  void _openPay() {
+    final isAuthenticated = context.read<AuthBloc>().state.isAuthenticated;
+    context.router.push(
+      isAuthenticated ? const PaymentCodeRoute() : const OnboardingRoute(),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     return AutoTabsRouter.pageView(
@@ -28,15 +36,26 @@ class _MainPageState extends State<MainPage> {
         HomeRoute(),
         // VoucherRoute(),
         OrderRoute(),
+        CommunityRoute(),
         ProfileRoute(),
       ],
       physics: const NeverScrollableScrollPhysics(),
-      builder: (context, child, pageController) => Scaffold(
-        body: child,
-        bottomNavigationBar: MainBottomNavbar(
-          tabsRouter: AutoTabsRouter.of(context),
-        ),
-      ),
+      builder: (context, child, pageController) {
+        // Docked FAB ikut naik ke atas keyboard; sembunyikan saat mengetik.
+        final isKeyboardOpen = MediaQuery.viewInsetsOf(context).bottom > 0;
+
+        return Scaffold(
+          body: child,
+          floatingActionButton: isKeyboardOpen
+              ? null
+              : MainPayButton(onPressed: _openPay),
+          floatingActionButtonLocation: const MainPayButtonLocation(),
+          bottomNavigationBar: MainBottomNavbar(
+            tabsRouter: AutoTabsRouter.of(context),
+            onPayTap: _openPay,
+          ),
+        );
+      },
     );
   }
 }