refactor: CSS 拆分 + auth 持久化提取 + 目录整理

- globals.css 拆分为 4 文件：tokens.css（颜色）/ transitions.css（过渡）/ base.css（重置）/ globals.css（入口）
- 提取 auth-persistence.ts 到 services/，解除 AppProvider→pages/login/hooks 反向依赖
- use-auth-state.ts 精简为纯 React Hook，持久化逻辑委托给 services/auth-persistence.ts
- components/common/ → components/ui/（目录名语义更清晰）
- TypeScript + Vite 构建通过

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/ui/LegalTextModal.tsx

@@ -0,0 +1,77 @@
+// ============================================================
+// LegalTextModal — 协议/法律文本展示弹窗
+// 从 src/assets/legal/ 加载 .txt 文件，主题适配渲染
+// ============================================================
+
+import { Modal, Typography } from 'antd';
+import { FileTextOutlined } from '@ant-design/icons';
+
+import { useTheme } from '@/components/ThemeProvider';
+
+// Vite ?raw 导入：将 .txt 内容作为字符串直接内联
+import serviceAgreement from '@/assets/legal/用户服务协议.txt?raw';
+import pointsAgreement from '@/assets/legal/积分充值服务协议.txt?raw';
+
+const { Paragraph } = Typography;
+
+/** 协议名称 → 文本内容映射 */
+const legalTexts: Record<string, { title: string; content: string }> = {
+   service: { title: '用户服务协议', content: serviceAgreement },
+   points: { title: '积分充值服务协议', content: pointsAgreement },
+};
+
+interface LegalTextModalProps {
+   open: boolean;
+   /** 协议标识：'service' | 'points' */
+   type: 'service' | 'points';
+   onClose: () => void;
+}
+
+export function LegalTextModal({ open, type, onClose }: LegalTextModalProps) {
+   const { isDark } = useTheme();
+   const legal = legalTexts[type];
+
+   if (!legal) return null;
+
+   return (
+      <Modal
+         open={open}
+         onCancel={onClose}
+         footer={null}
+         width={640}
+         centered
+         title={
+            <span className="flex items-center gap-2">
+               <FileTextOutlined />
+               {legal.title}
+            </span>
+         }
+         styles={{
+            body: {
+               maxHeight: '60vh',
+               overflowY: 'auto',
+               padding: '20px 24px',
+               background: isDark ? '#1A1730' : '#FFFFFF',
+               color: isDark ? '#E8E6F0' : '#1E1B4B',
+               fontSize: 14,
+               lineHeight: 2,
+               whiteSpace: 'pre-wrap',
+               wordBreak: 'break-word',
+               fontFamily: 'var(--font-family-base)',
+            },
+         }}
+      >
+         <Paragraph
+            style={{
+               color: isDark ? '#E8E6F0' : '#1E1B4B',
+               fontSize: 14,
+               lineHeight: 2,
+               whiteSpace: 'pre-wrap',
+               margin: 0,
+            }}
+         >
+            {legal.content}
+         </Paragraph>
+      </Modal>
+   );
+}