Add optional KYC flow and service-backed account limits

frontend/app/lib/routing/router.dart

@@ -1,37 +1,50 @@
 import 'dart:convert';
 
+import 'package:flutter/widgets.dart';
+
 import 'package:go_router/go_router.dart';
 
 import '../auth/page.dart';
+import '../kyc/page.dart';
 import '../verification/page.dart';
 import 'routes.dart';
 
-GoRouter createAppRouter() => GoRouter(
-  // Signup email is an in-memory navigation extra, never browser-history data.
-  extraCodec: const _TransientExtras(),
-  routes: [
-    GoRoute(
-      path: '/',
-      name: AppRoutes.login,
-      builder: (context, state) => const AuthPage(),
-    ),
-    GoRoute(
-      path: '/verification-sent',
-      name: AppRoutes.verificationSent,
-      builder: (context, state) => VerificationPage(
-        email: state.extra is String ? state.extra as String : null,
+GoRouter createAppRouter() {
+  final identityKey = GlobalKey<IdentityPageState>();
+  return GoRouter(
+    // Signup email is an in-memory navigation extra, never browser-history data.
+    extraCodec: const _TransientExtras(),
+    routes: [
+      GoRoute(
+        path: '/identity',
+        name: AppRoutes.identity,
+        builder: (context, state) => IdentityPage(key: identityKey),
+        onExit: (context, state) async =>
+            await identityKey.currentState?.allowExit() ?? true,
       ),
-    ),
-    GoRoute(
-      path: '/verify-email',
-      name: AppRoutes.verifyEmail,
-      builder: (context, state) =>
-          VerificationPage(token: state.uri.queryParameters['token'] ?? ''),
-    ),
-  ],
-  // Preserve the existing fallback, and keep the visible URL canonical.
-  onException: (context, state, router) => router.goNamed(AppRoutes.login),
-);
+      GoRoute(
+        path: '/',
+        name: AppRoutes.login,
+        builder: (context, state) => const AuthPage(),
+      ),
+      GoRoute(
+        path: '/verification-sent',
+        name: AppRoutes.verificationSent,
+        builder: (context, state) => VerificationPage(
+          email: state.extra is String ? state.extra as String : null,
+        ),
+      ),
+      GoRoute(
+        path: '/verify-email',
+        name: AppRoutes.verifyEmail,
+        builder: (context, state) =>
+            VerificationPage(token: state.uri.queryParameters['token'] ?? ''),
+      ),
+    ],
+    // Preserve the existing fallback, and keep the visible URL canonical.
+    onException: (context, state, router) => router.goNamed(AppRoutes.login),
+  );
+}
 
 class _TransientExtras extends Codec<Object?, Object?> {
   const _TransientExtras();

frontend/app/lib/routing/routes.dart

@@ -1,4 +1,5 @@
 abstract final class AppRoutes {
+  static const identity = 'identity';
   static const login = 'login';
   static const verificationSent = 'verification-sent';
   static const verifyEmail = 'verify-email';