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

lib/widgets/risk/risk_list_widgets.dart

@@ -0,0 +1,186 @@
+import 'package:flutter/material.dart';
+
+import '../../config/strings.dart';
+
+/// 全宽的「添加到列表」按钮，样式统一。
+class RiskAddButton extends StatelessWidget {
+  final VoidCallback? onPressed;
+
+  const RiskAddButton({super.key, this.onPressed});
+
+  @override
+  Widget build(BuildContext context) {
+    return SizedBox(
+      width: double.infinity,
+      child: OutlinedButton.icon(
+        onPressed: onPressed,
+        icon: const Icon(Icons.add, size: 18),
+        label: const Text(AppStrings.listAddButton),
+        style: OutlinedButton.styleFrom(
+          padding: const EdgeInsets.symmetric(vertical: 12),
+          shape: RoundedRectangleBorder(
+            borderRadius: BorderRadius.circular(10),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+/// 待提交列表：标题带数量，空列表时显示提示。
+class RiskPendingList extends StatelessWidget {
+  final String title;
+  final String emptyHint;
+  final int count;
+  final List<Widget> rows;
+
+  const RiskPendingList({
+    super.key,
+    required this.title,
+    required this.emptyHint,
+    required this.count,
+    required this.rows,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        const SizedBox(height: 14),
+        Text(
+          '$title ($count)',
+          style: theme.textTheme.labelLarge?.copyWith(
+            color: theme.colorScheme.primary,
+            fontWeight: FontWeight.w600,
+          ),
+        ),
+        const SizedBox(height: 6),
+        if (count == 0)
+          Text(
+            emptyHint,
+            style: theme.textTheme.bodySmall?.copyWith(
+              color: theme.colorScheme.onSurfaceVariant,
+            ),
+          )
+        else
+          ...rows,
+      ],
+    );
+  }
+}
+
+/// 待提交列表的一行：等宽文本 + 删除按钮。
+class RiskPendingRow extends StatelessWidget {
+  final String leading;
+  final String trailing;
+  final VoidCallback onRemove;
+  final bool enabled;
+
+  const RiskPendingRow({
+    super.key,
+    required this.leading,
+    required this.trailing,
+    required this.onRemove,
+    this.enabled = true,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return Row(
+      children: [
+        Expanded(
+          child: Text(
+            '$leading  $trailing',
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
+            style: theme.textTheme.bodySmall?.copyWith(
+              fontFamily: 'monospace',
+            ),
+          ),
+        ),
+        IconButton(
+          icon: const Icon(Icons.close, size: 18),
+          tooltip: AppStrings.listRemoveTooltip,
+          onPressed: enabled ? onRemove : null,
+          color: theme.colorScheme.onSurfaceVariant,
+          visualDensity: VisualDensity.compact,
+        ),
+      ],
+    );
+  }
+}
+
+/// 风险页通用下拉框（圆角 10、内容内边距 14）。
+class RiskDropdownField<T> extends StatelessWidget {
+  final T value;
+  final String label;
+  final List<DropdownMenuItem<T>> items;
+  final ValueChanged<T>? onChanged;
+  final bool enabled;
+
+  const RiskDropdownField({
+    super.key,
+    required this.value,
+    required this.label,
+    required this.items,
+    required this.onChanged,
+    this.enabled = true,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return DropdownButtonFormField<T>(
+      initialValue: value,
+      decoration: InputDecoration(
+        labelText: label,
+        border: OutlineInputBorder(
+          borderRadius: BorderRadius.circular(10),
+        ),
+        contentPadding: const EdgeInsets.all(14),
+      ),
+      items: items,
+      onChanged: !enabled || onChanged == null
+          ? null
+          : (v) {
+              if (v == null) return;
+              onChanged!(v);
+            },
+    );
+  }
+}
+
+/// 与 [RiskDropdownField] 配对的普通文本输入框，保持同样的圆角与内边距。
+class RiskNumberField extends StatelessWidget {
+  final TextEditingController controller;
+  final String label;
+  final String hint;
+  final bool enabled;
+
+  const RiskNumberField({
+    super.key,
+    required this.controller,
+    required this.label,
+    required this.hint,
+    this.enabled = true,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return TextField(
+      controller: controller,
+      enabled: enabled,
+      keyboardType: TextInputType.number,
+      decoration: InputDecoration(
+        labelText: label,
+        hintText: hint,
+        border: OutlineInputBorder(
+          borderRadius: BorderRadius.circular(10),
+        ),
+        contentPadding: const EdgeInsets.all(14),
+      ),
+    );
+  }
+}