feat: Enhance CLI and GUI to support configurable game data directory persistence

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_flutter/lib/managers/desktop_windowing_support.dart

@@ -1,6 +1,8 @@
 library;
 
 import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
+import 'package:window_manager/window_manager.dart';
 
 /// Whether desktop window-management APIs are expected to work on this host.
 bool get supportsDesktopWindowing {
@@ -15,3 +17,21 @@ bool get supportsDesktopWindowing {
     _ => false,
   };
 }
+
+/// Ensures desktop windowing plugin state is initialized when supported.
+///
+/// This safely no-ops on non-desktop targets and in hosts where the plugin is
+/// not registered.
+Future<void> ensureDesktopWindowingInitialized({
+  WindowManager? windowing,
+}) async {
+  if (!supportsDesktopWindowing) {
+    return;
+  }
+
+  try {
+    await (windowing ?? windowManager).ensureInitialized();
+  } on MissingPluginException {
+    // No-op on hosts where the window manager plugin is unavailable.
+  }
+}

packages/wolf_3d_flutter/lib/managers/game_data_directory_persistence.dart

@@ -0,0 +1,4 @@
+library;
+
+export 'game_data_directory_persistence_stub.dart'
+    if (dart.library.io) 'game_data_directory_persistence_io.dart';

packages/wolf_3d_flutter/lib/managers/game_data_directory_persistence_io.dart

@@ -0,0 +1,99 @@
+library;
+
+import 'dart:convert';
+import 'dart:io';
+
+/// Persists the configured game-data directory path as JSON.
+class DefaultGameDataDirectoryPersistence {
+  DefaultGameDataDirectoryPersistence({String? filePath})
+    : _filePath = filePath;
+
+  final String? _filePath;
+  String? _resolvedPath;
+
+  /// Absolute JSON file path used for persistence.
+  String get filePath {
+    if (_resolvedPath != null) {
+      return _resolvedPath!;
+    }
+
+    if (_filePath != null && _filePath.isNotEmpty) {
+      _resolvedPath = _filePath;
+      return _resolvedPath!;
+    }
+
+    _resolvedPath = '$platformConfigDir/data_source.json';
+    return _resolvedPath!;
+  }
+
+  /// Loads a previously persisted data-directory path.
+  Future<String?> loadDataDirectory() async {
+    try {
+      final file = File(filePath);
+      if (!await file.exists()) {
+        return null;
+      }
+
+      final raw = await file.readAsString();
+      if (raw.isEmpty) {
+        return null;
+      }
+
+      final decoded = jsonDecode(raw);
+      if (decoded is! Map<String, Object?>) {
+        return null;
+      }
+
+      final Object? value = decoded['dataDirectory'];
+      if (value is! String) {
+        return null;
+      }
+
+      final normalized = value.trim();
+      return normalized.isEmpty ? null : normalized;
+    } catch (_) {
+      return null;
+    }
+  }
+
+  /// Persists [directoryPath] for future startups.
+  Future<void> saveDataDirectory(String? directoryPath) async {
+    try {
+      final normalized = directoryPath?.trim();
+      final file = File(filePath);
+
+      await file.parent.create(recursive: true);
+      if (normalized == null || normalized.isEmpty) {
+        if (await file.exists()) {
+          await file.delete();
+        }
+        return;
+      }
+
+      final payload = jsonEncode(<String, Object>{
+        'dataDirectory': normalized,
+      });
+      await file.writeAsString(payload, flush: true);
+    } catch (_) {
+      // Best-effort only.
+    }
+  }
+
+  String get platformConfigDir {
+    if (Platform.isLinux) {
+      final String xdg = Platform.environment['XDG_CONFIG_HOME'] ?? '';
+      final String home = Platform.environment['HOME'] ?? '.';
+      return xdg.isNotEmpty ? '$xdg/wolf3d' : '$home/.config/wolf3d';
+    }
+    if (Platform.isMacOS) {
+      final String home = Platform.environment['HOME'] ?? '.';
+      return '$home/Library/Application Support/wolf3d';
+    }
+    if (Platform.isWindows) {
+      final String appData = Platform.environment['APPDATA'] ?? '.';
+      return '$appData/wolf3d';
+    }
+    final String home = Platform.environment['HOME'] ?? '.';
+    return '$home/.config/wolf3d';
+  }
+}

packages/wolf_3d_flutter/lib/managers/game_data_directory_persistence_stub.dart

@@ -0,0 +1,14 @@
+library;
+
+/// No-op persistence used on platforms without `dart:io` support.
+class DefaultGameDataDirectoryPersistence {
+  DefaultGameDataDirectoryPersistence({String? filePath});
+
+  /// Loads a previously persisted data-directory path.
+  Future<String?> loadDataDirectory() async {
+    return null;
+  }
+
+  /// Persists [directoryPath] for future startups.
+  Future<void> saveDataDirectory(String? directoryPath) async {}
+}