feat: support smol:// QR sharing, deep links and in-dialog scanning

lib/presentation/routes/app_router.dart

@@ -1,10 +1,25 @@
 import "package:auto_route/auto_route.dart";
+import "package:flutter/material.dart";
 import "package:flutter_riverpod/flutter_riverpod.dart";
 
 import "package:smol_mail/presentation/routes/home_guard.dart";
 import "package:smol_mail/presentation/routes/identity_guard.dart";
 import "app_router.gr.dart";
 
+/// A DialogRoute is a PageRoute whose settings carry the AutoRoutePage, so
+/// auto_route's setNewRoutePath — which pops pageless top routes before
+/// resolving a platform link — leaves dialog pages standing.
+Route<T> dialogRouteBuilder<T>(
+  BuildContext context,
+  Widget child,
+  AutoRoutePage<T> page,
+) =>
+    DialogRoute<T>(
+      context: context,
+      settings: page,
+      builder: (ctx) => child,
+    );
+
 @AutoRouterConfig(replaceInRouteName: "Screen,Route")
 class AppRouter extends RootStackRouter {
   final WidgetRef ref;
@@ -44,5 +59,11 @@ class AppRouter extends RootStackRouter {
           path: "/contact",
           guards: [IdentityGuard(ref)],
         ),
+        CustomRoute(
+          page: ImportContactDialogRoute.page,
+          path: "/import",
+          customRouteBuilder: dialogRouteBuilder,
+          guards: [IdentityGuard(ref)],
+        ),
       ];
 }