feat: 添加环境配置和动态主页URL

lib/config/app_config.dart

@@ -0,0 +1,32 @@
+enum Environment {
+  production,
+}
+
+class AppConfig {
+  static const Environment currentEnvironment = Environment.production;
+
+  static final Map<Environment, List<String>> _environmentHosts = {
+    Environment.production: [
+      'h5-im.imharry.work',
+    ],
+  };
+
+  static List<String> get environmentHosts {
+    return _environmentHosts[currentEnvironment] ?? const [];
+  }
+
+  static String get homeUrl {
+    final host = environmentHosts.isNotEmpty
+        ? environmentHosts.first
+        : 'h5-im.imharry.work';
+    return _normalizeHomeUrl(host);
+  }
+
+  static String _normalizeHomeUrl(String host) {
+    final value = host.trim();
+    if (value.startsWith('http://') || value.startsWith('https://')) {
+      return value.endsWith('/') ? value : '$value/';
+    }
+    return 'https://$value/';
+  }
+}