refactor: 拆分主页与公共组件，扫码登录改走 WinHTTP

- 抽出 lib/core 的日期/JSON 工具，收敛各页重复解析
- 主页与音乐风险页拆成组件，风险功能共用一套运行框架
- 修复设置页作为主页页签保存时弹掉根路由导致的黑屏
- 登录对齐 Astral aimedb 协议：84 位二维码校验、签名与请求头修正，
  补 GlobalSign 中间证书；Windows 改用 WinHTTP 绕过服务端对
  BoringSSL 的 TLS 指纹拦截（证书校验保持开启）
- 补开发预览数据与测试

test/core/date_time_format_test.dart

@@ -0,0 +1,23 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:ichino/core/date_time_format.dart';
+
+void main() {
+  test('上海时区固定为 UTC+8', () {
+    expect(shanghaiOffset, const Duration(hours: 8));
+    expect(
+      shanghaiFromUnixSeconds(0),
+      DateTime.utc(1970, 1, 1, 8),
+    );
+  });
+
+  test('formatDate 补零', () {
+    expect(formatDate(DateTime(2026, 1, 5, 7, 3, 9)), '2026-01-05');
+    expect(formatDate(DateTime(2026, 12, 31, 23, 59, 59)), '2026-12-31');
+  });
+
+  test('formatDateTime 与 formatPlayDateTime 的秒与小数位', () {
+    final dt = DateTime(2026, 10, 2, 22, 19, 46);
+    expect(formatDateTime(dt), '2026-10-02 22:19:46');
+    expect(formatPlayDateTime(dt), '2026-10-02 22:19:46.0');
+  });
+}

test/core/json_value_test.dart

@@ -0,0 +1,84 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:ichino/core/json_value.dart';
+
+void main() {
+  group('jsonInt', () {
+    test('int / num / 数字字符串都能读出来', () {
+      expect(jsonInt(12), 12);
+      expect(jsonInt(12.9), 12);
+      expect(jsonInt('42'), 42);
+      expect(jsonInt('-3'), -3);
+    });
+
+    test('null、非数字字符串、其他类型退回 fallback', () {
+      expect(jsonInt(null), 0);
+      expect(jsonInt('12abc'), 0);
+      expect(jsonInt('12abc', fallback: -1), -1);
+      expect(jsonInt({'v': 1}), 0);
+    });
+  });
+
+  group('jsonDouble', () {
+    test('int / double / 数字字符串都能读出来', () {
+      expect(jsonDouble(3), 3.0);
+      expect(jsonDouble(3.25), 3.25);
+      expect(jsonDouble('3.25'), 3.25);
+    });
+
+    test('解析失败退回 fallback', () {
+      expect(jsonDouble(null), 0.0);
+      expect(jsonDouble('x'), 0.0);
+      expect(jsonDouble('x', fallback: 1.5), 1.5);
+    });
+  });
+
+  group('jsonBool', () {
+    test('bool、数字、常见字符串形式', () {
+      expect(jsonBool(true), isTrue);
+      expect(jsonBool(false), isFalse);
+      expect(jsonBool(1), isTrue);
+      expect(jsonBool(0), isFalse);
+      expect(jsonBool('1'), isTrue);
+      expect(jsonBool(' TRUE '), isTrue);
+      expect(jsonBool('true'), isTrue);
+      expect(jsonBool('0'), isFalse);
+      expect(jsonBool('false'), isFalse);
+    });
+
+    test('无法判断时用 fallback', () {
+      expect(jsonBool(null), isFalse);
+      expect(jsonBool(null, fallback: true), isTrue);
+      expect(jsonBool('yes'), isFalse);
+    });
+  });
+
+  group('jsonString', () {
+    test('null 用 fallback，其他类型转字符串', () {
+      expect(jsonString(null), '');
+      expect(jsonString(null, fallback: '-'), '-');
+      expect(jsonString(7), '7');
+      expect(jsonString('abc'), 'abc');
+    });
+  });
+
+  group('jsonMap / jsonMapList', () {
+    test('jsonMap 只接受 Map<String, dynamic>', () {
+      final map = <String, dynamic>{'a': 1};
+      expect(jsonMap(map), same(map));
+      expect(jsonMap(null), isEmpty);
+      expect(jsonMap([1, 2]), isEmpty);
+    });
+
+    test('jsonMapList 丢掉非 Map 元素，其余原样保留', () {
+      final rows = [
+        <String, dynamic>{'id': 1},
+        'oops',
+        null,
+        <String, dynamic>{'id': 2},
+      ];
+      expect(jsonMapList(rows).map((e) => e['id']), [1, 2]);
+      expect(jsonMapList(null), isEmpty);
+      expect(jsonMapList(<String, dynamic>{'id': 1}), isEmpty);
+    });
+  });
+}