refactor: Simplify navigation by removing main tabs

Removed the main tab navigation, which previously included "Game" and "Mine" tabs. The app now defaults directly to the `GamePage`.

- Deleted `MainIndexPage`, `MinePage`, and their associated localization files.
- Updated the routing configuration in `lib/route.dart` to remove the `StatefulShellRoute` and direct the root path `/` to `GamePage`.
- Moved the settings button from the now-deleted `MinePage` to the `AppBar` of the `GamePage`.

Author: liplum

lib/route.dart

@@ -3,44 +3,23 @@ import 'package:escape_wild/ui/game/backpack/backpack.dart';
 import 'package:escape_wild/ui/game/craft/craft.dart';
 import 'package:escape_wild/ui/game/index.dart';
 import 'package:escape_wild/ui/main/game.dart';
-import 'package:escape_wild/ui/main/index.dart';
-import 'package:escape_wild/ui/main/mine.dart';
 import 'package:flutter/widgets.dart';
 import 'package:go_router/go_router.dart';
 
-final _$mainGame = GlobalKey<NavigatorState>();
-final _$mainMine = GlobalKey<NavigatorState>();
 final _$gameAction = GlobalKey<NavigatorState>();
 final _$gameBackpack = GlobalKey<NavigatorState>();
 final _$gameCraft = GlobalKey<NavigatorState>();
 
 RoutingConfig buildRoutingConfig() {
   return RoutingConfig(
     routes: [
-      GoRoute(path: "/", redirect: (ctx, state) => "/main/game"),
+      GoRoute(path: "/", builder: (ctx, state) => GamePage()),
       GoRoute(
         path: "/main",
         redirect: (ctx, state) {
           if (state.fullPath == "/main") return "/main/game";
           return null;
         },
-        routes: [
-          StatefulShellRoute.indexedStack(
-            builder: (ctx, state, navigationShell) {
-              return MainIndexPage(navigationShell: navigationShell);
-            },
-            branches: [
-              StatefulShellBranch(
-                navigatorKey: _$mainGame,
-                routes: [GoRoute(path: "/game", builder: (ctx, state) => const GamePage())],
-              ),
-              StatefulShellBranch(
-                navigatorKey: _$mainMine,
-                routes: [GoRoute(path: "/mine", builder: (ctx, state) => const MinePage())],
-              ),
-            ],
-          ),
-        ],
       ),
       GoRoute(
         path: "/game",

lib/ui/main/game.dart

@@ -4,6 +4,9 @@ import 'package:go_router/go_router.dart';
 import 'package:hive_flutter/adapters.dart';
 import 'package:rettulf/rettulf.dart';
 import 'package:easy_localization/easy_localization.dart';
+import 'package:tabler_icons/tabler_icons.dart';
+
+import 'settings.dart';
 
 part 'game.i18n.dart';
 
@@ -18,7 +21,19 @@ class _GamePageState extends State<GamePage> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(centerTitle: true, elevation: 0, backgroundColor: Colors.transparent),
+      appBar: AppBar(
+        centerTitle: true,
+        elevation: 0,
+        backgroundColor: Colors.transparent,
+        actions: [
+          IconButton(
+            onPressed: () {
+              context.navigator.push(MaterialPageRoute(builder: (_) => const SettingsPage()));
+            },
+            icon: const Icon(TablerIcons.settings),
+          ),
+        ],
+      ),
       body: buildBody(),
     );
   }