feat: auto-set Steam Launch Options after MelonLoader install

lib/src/core/dancing_line_game.dart

@@ -20,6 +20,12 @@ class DancingLineGame extends Game {
   @override
   String? get steamAppId => '4395300';
 
+  @override
+  List<String> windowsExecutableNames() => const [
+        'Dancing Line.exe',
+        'DancingLine.exe',
+      ];
+
   @override
   List<String> getSteamInstallFolderNames() => const [
         'Dancing Line',

lib/src/core/game.dart

@@ -76,6 +76,38 @@ abstract class Game {
   // Folder names Steam may use under steamapps/common.
   List<String> getSteamInstallFolderNames() => [name];
 
+  /// Candidate Windows executable file names, used to detect a Proton/Wine
+  /// install on a non-Windows host. Subclasses override when the Windows build
+  /// uses a name that differs from `<name>.exe`.
+  List<String> windowsExecutableNames() => ['$name.exe'];
+
+  /// True when this install is the Windows build running through Proton/Wine —
+  /// i.e. a Windows .exe is present on a non-Windows host.
+  bool isProtonOrWineInstall(String gamePath) {
+    if (Platform.isWindows) return false;
+    for (final exe in windowsExecutableNames()) {
+      if (File(p.join(gamePath, exe)).existsSync()) return true;
+    }
+    return false;
+  }
+
+  /// The exact Steam Launch Options string MelonLoader needs for this install,
+  /// or null when none is required (Windows, where the bootstrap injects
+  /// without a wrapper). Used to auto-write Steam's localconfig.vdf after
+  /// install and to populate the manual guide.
+  String? steamLaunchOptionsValue(String gamePath) {
+    if (Platform.isWindows) return null;
+    if (isProtonOrWineInstall(gamePath)) {
+      return r'WINEDLLOVERRIDES="winhttp=n,b" %command%';
+    }
+    if (Platform.isMacOS) {
+      // Steam on macOS does not resolve relative paths; use the absolute script.
+      return '"${p.join(gamePath, 'setup_helper.sh')}" %command%';
+    }
+    // Linux native
+    return './setup_helper.sh %command%';
+  }
+
   String? findSteamInstallPath() {
     for (final candidate in getSteamInstallCandidatePaths()) {
       if (isValidGamePath(candidate)) {

lib/src/core/installer_state.dart

@@ -4,6 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:path/path.dart' as p;
 import 'game.dart';
+import 'steam_config.dart';
 import 'adofai_game.dart';
 import 'dancing_line_game.dart';
 import 'rhythm_doctor_game.dart';
@@ -44,6 +45,11 @@ class InstallerState extends ChangeNotifier {
   bool _isProcessing = false;
   String? _statusMessage;
 
+  // Whether the last install auto-wrote Steam's Launch Options for this game,
+  // and whether Steam needs a full restart for that write to take effect.
+  bool _steamLaunchOptionsApplied = false;
+  bool _steamLaunchOptionsNeedRestart = false;
+
   // Mod Update Cache & Status
   final Map<String, ModItem> _onlineModsCache = {};
   List<String> _modsWithUpdates = [];
@@ -73,6 +79,9 @@ class InstallerState extends ChangeNotifier {
   bool get isUmmDetected => _isUmmDetected;
   String get loaderVersion => _loaderVersion;
   bool get isLoaderOutdated => _isLoaderOutdated;
+
+  bool get steamLaunchOptionsApplied => _steamLaunchOptionsApplied;
+  bool get steamLaunchOptionsNeedRestart => _steamLaunchOptionsNeedRestart;
 
   String get locale => _locale;
 
@@ -325,6 +334,8 @@ class InstallerState extends ChangeNotifier {
     _isProcessing = true;
     _progress = 0.0;
     _statusMessage = t('status_loader_downloading');
+    _steamLaunchOptionsApplied = false;
+    _steamLaunchOptionsNeedRestart = false;
     notifyListeners();
 
     var installTimedOut = false;
@@ -371,6 +382,10 @@ class InstallerState extends ChangeNotifier {
       );
       await DebugLog.info('Core MelonLoader install completed');
 
+      // Point Steam's Launch Options at the setup_helper.sh wrapper so the
+      // loader actually injects on launch (no-op on Windows / unknown appid).
+      await _applySteamLaunchOptions();
+
       if (_isUmmDetected && installUmmCompat) {
         _statusMessage = t('status_loader_checking_ummcompat');
         notifyListeners();
@@ -412,6 +427,58 @@ class InstallerState extends ChangeNotifier {
     }
   }
 
+  // Steam Launch Options 자동 설정 (localconfig.vdf 직접 편집)
+  Future<void> _applySteamLaunchOptions() async {
+    final appId = game.steamAppId;
+    final value = game.steamLaunchOptionsValue(_gamePath);
+    if (appId == null || value == null) {
+      // Windows (no wrapper needed) or unknown app id — nothing to write.
+      return;
+    }
+    try {
+      final result = await SteamConfig.setLaunchOptions(
+        appId: appId,
+        value: value,
+      );
+      _steamLaunchOptionsApplied = result.applied;
+      _steamLaunchOptionsNeedRestart = result.applied && result.steamRunning;
+      await DebugLog.info(
+        'Steam launch options: applied=${result.applied} '
+        'updated=${result.updatedCount} configFound=${result.configFound} '
+        'steamRunning=${result.steamRunning} appId=$appId',
+      );
+    } catch (e, stackTrace) {
+      _steamLaunchOptionsApplied = false;
+      await DebugLog.error(
+        'Failed to set Steam launch options',
+        error: e,
+        stackTrace: stackTrace,
+      );
+    }
+  }
+
+  // Steam Launch Options 정리 (우리가 설정한 래퍼만 제거)
+  Future<void> _clearSteamLaunchOptions() async {
+    final appId = game.steamAppId;
+    if (appId == null) return;
+    try {
+      final result = await SteamConfig.clearLaunchOptions(appId: appId);
+      await DebugLog.info(
+        'Cleared Steam launch options: updated=${result.updatedCount} '
+        'appId=$appId',
+      );
+    } catch (e, stackTrace) {
+      await DebugLog.error(
+        'Failed to clear Steam launch options',
+        error: e,
+        stackTrace: stackTrace,
+      );
+    } finally {
+      _steamLaunchOptionsApplied = false;
+      _steamLaunchOptionsNeedRestart = false;
+    }
+  }
+
   // UMM 호환 모드(ummcompat) 설치
   Future<void> installUmmCompat() async {
     if (_isProcessing || !_isValidPath) return;
@@ -500,6 +567,7 @@ class InstallerState extends ChangeNotifier {
 
     try {
       await game.uninstallLoader(_gamePath);
+      await _clearSteamLaunchOptions();
       _statusMessage = t('status_loader_uninstall_success');
     } catch (e) {
       _statusMessage = t('status_loader_uninstall_failed', args: {'error': describeAppError(e)});

lib/src/core/localization.dart

@@ -92,6 +92,9 @@ class Localization {
       'installed_copied_clipboard': '클립보드에 복사되었습니다.',
       'installed_err_file_picker': '파일 선택 중 오류가 발생했습니다: {error}',
       'installed_launch_guide_title': '💡 비윈도우 OS 추가 안내 사항',
+      'installed_launch_auto_set': '✓ 스팀 실행 옵션이 자동으로 설정되었습니다.',
+      'installed_launch_auto_set_restart':
+          '변경 사항을 적용하려면 스팀을 완전히 종료한 후 다시 실행하세요.',
       'installed_btn_copy_native_launch': '네이티브 시작 옵션 복사',
       'installed_btn_copy_proton_launch': 'Proton 시작 옵션 복사',
       'settings_btn_check_updates': '업데이트 확인',
@@ -375,6 +378,10 @@ class Localization {
       'installed_copied_clipboard': 'Copied to clipboard.',
       'installed_err_file_picker': 'An error occurred while picking file: {error}',
       'installed_launch_guide_title': '💡 Additional Guide for Non-Windows OS',
+      'installed_launch_auto_set':
+          '✓ Steam launch options were configured automatically.',
+      'installed_launch_auto_set_restart':
+          'Fully quit and reopen Steam for the change to take effect.',
       'installed_btn_copy_native_launch': 'Copy Native Launch Options',
       'installed_btn_copy_proton_launch': 'Copy Proton Launch Options',
       'settings_btn_check_updates': 'Check for Updates',
@@ -656,6 +663,8 @@ class Localization {
       'installed_copied_clipboard': '已复制到剪贴板。',
       'installed_err_file_picker': '选择文件时出错: {error}',
       'installed_launch_guide_title': '💡 非 Windows 系统额外说明',
+      'installed_launch_auto_set': '✓ 已自动配置 Steam 启动选项。',
+      'installed_launch_auto_set_restart': '请完全退出并重新打开 Steam 以使更改生效。',
       'installed_btn_copy_native_launch': '复制原生启动选项',
       'installed_btn_copy_proton_launch': '复制 Proton 启动选项',
       'settings_btn_check_updates': '检查更新',

lib/src/core/rhythm_doctor_game.dart

@@ -20,6 +20,12 @@ class RhythmDoctorGame extends Game {
   @override
   String? get steamAppId => '774181';
 
+  @override
+  List<String> windowsExecutableNames() => const [
+        'Rhythm Doctor.exe',
+        'RhythmDoctor.exe',
+      ];
+
   @override
   List<String> getSteamInstallFolderNames() => const [
         'Rhythm Doctor',