feat: 添加README以及example项目，修复plugin的路径，新建basic_intl的本地依赖

packages/basic_intl/lib/basic_intl.dart

@@ -0,0 +1,3 @@
+library basic_intl;
+
+export 'src/intl.dart';

packages/basic_intl/lib/intl.dart

@@ -0,0 +1,3 @@
+library basic_intl;
+
+export 'src/intl.dart';

packages/basic_intl/lib/src/intl.dart

@@ -0,0 +1,32 @@
+import 'dart:ui';
+
+class Intl {
+  static String _currentLocale = 'zh_CN';
+
+  /// 获取当前语言环境
+  static String getCurrentLocale() {
+    // 尝试从系统获取语言环境
+    try {
+      final systemLocale = PlatformDispatcher.instance.locale;
+      _currentLocale = '${systemLocale.languageCode}_${systemLocale.countryCode ?? 'CN'}';
+    } catch (e) {
+      _currentLocale = 'zh_CN';
+    }
+    return _currentLocale;
+  }
+
+  /// 设置当前语言环境
+  static void setCurrentLocale(String locale) {
+    _currentLocale = locale;
+  }
+
+  /// 判断是否为中文环境
+  static bool isChineseLocale() {
+    return getCurrentLocale().startsWith('zh');
+  }
+
+  /// 判断是否为英文环境
+  static bool isEnglishLocale() {
+    return getCurrentLocale().startsWith('en');
+  }
+}