feat(frontend): 前端界面优化与使用统计功能增强 (#46)

* feat(frontend): 前端界面优化与使用统计功能增强

主要改动:

1. 表格布局统一优化
   - 新增 TablePageLayout 通用布局组件
   - 统一所有管理页面的表格样式和交互
   - 优化 DataTable、Pagination、Select 等通用组件

2. 使用统计功能增强
   - 管理端: 添加完整的筛选和显示功能
   - 用户端: 完善 API Key 列显示
   - 后端: 优化使用统计数据结构和查询

3. 账户组件优化
   - 优化 AccountStatsModal、AccountUsageCell 等组件
   - 统一进度条和统计显示样式

4. 其他改进
   - 完善中英文国际化
   - 统一页面样式和交互体验
   - 优化各视图页面的响应式布局

* fix(test): 修复 stubUsageLogRepo.ListWithFilters 测试 stub

测试用例 GET /api/v1/usage 返回 500 是因为 stub 方法未实现，
现在正确返回基于 UserID 过滤的日志数据。

* feat(frontend): 统一日期时间显示格式

**主要改动**:
1. 增强 utils/format.ts:
   - 新增 formatDateOnly() - 格式: YYYY-MM-DD
   - 新增 formatDateTime() - 格式: YYYY-MM-DD HH:mm:ss

2. 全局替换视图中的格式化函数:
   - 移除各视图中的自定义 formatDate 函数
   - 统一导入使用 @/utils/format 中的函数
   - created_at/updated_at 使用 formatDateTime
   - expires_at 使用 formatDateOnly

3. 受影响的视图 (8个):
   - frontend/src/views/user/KeysView.vue
   - frontend/src/views/user/DashboardView.vue
   - frontend/src/views/user/UsageView.vue
   - frontend/src/views/user/RedeemView.vue
   - frontend/src/views/admin/UsersView.vue
   - frontend/src/views/admin/UsageView.vue
   - frontend/src/views/admin/RedeemView.vue
   - frontend/src/views/admin/SubscriptionsView.vue

**效果**:
- 日期统一显示为 YYYY-MM-DD
- 时间统一显示为 YYYY-MM-DD HH:mm:ss
- 提升可维护性，避免格式不一致

* fix(frontend): 补充遗漏的时间格式化统一

**补充修复**（基于 code review 发现的遗漏）:

1. 增强 utils/format.ts:
   - 新增 formatTime() - 格式: HH:mm

2. 修复 4 个遗漏的文件:
   - src/views/admin/UsersView.vue
     * 删除 formatExpiresAt()，改用 formatDateTime()
     * 修复订阅过期时间 tooltip 显示格式不一致问题

   - src/views/user/ProfileView.vue
     * 删除 formatMemberSince()，改用 formatDate(date, 'YYYY-MM')
     * 统一会员起始时间显示格式

   - src/views/user/SubscriptionsView.vue
     * 修改 formatExpirationDate() 使用 formatDateOnly()
     * 保留天数计算逻辑

   - src/components/account/AccountStatusIndicator.vue
     * 删除本地 formatTime()，改用 utils/format 中的统一函数
     * 修复 rate limit 和 overload 重置时间显示

**验证**:
- TypeScript 类型检查通过 ✓
- 前端构建成功 ✓
- 所有剩余的 toLocaleString() 都是数字格式化，属于正确用法 ✓

**效果**:
- 订阅过期时间统一为 YYYY-MM-DD HH:mm:ss
- 会员起始时间统一为 YYYY-MM
- 重置时间统一为 HH:mm
- 消除所有不规范的原生 locale 方法调用

frontend/src/i18n/locales/en.ts

@@ -30,13 +30,56 @@ export default {
       title: 'Supported Providers',
       description: 'Unified API interface for AI services',
       supported: 'Supported',
-      soon: 'Soon'
+      soon: 'Soon',
+      claude: 'Claude',
+      gemini: 'Gemini',
+      more: 'More'
     },
     footer: {
       allRightsReserved: 'All rights reserved.'
     }
   },
 
+  // Setup Wizard
+  setup: {
+    title: 'Sub2API Setup',
+    description: 'Configure your Sub2API instance',
+    database: {
+      title: 'Database Configuration',
+      host: 'Host',
+      port: 'Port',
+      username: 'Username',
+      password: 'Password',
+      databaseName: 'Database Name',
+      sslMode: 'SSL Mode',
+      ssl: {
+        disable: 'Disable',
+        require: 'Require',
+        verifyCa: 'Verify CA',
+        verifyFull: 'Verify Full'
+      }
+    },
+    redis: {
+      title: 'Redis Configuration',
+      host: 'Host',
+      port: 'Port',
+      password: 'Password (optional)',
+      database: 'Database'
+    },
+    admin: {
+      title: 'Admin Account',
+      email: 'Email',
+      password: 'Password',
+      confirmPassword: 'Confirm Password'
+    },
+    ready: {
+      title: 'Ready to Install',
+      database: 'Database',
+      redis: 'Redis',
+      adminEmail: 'Admin Email'
+    }
+  },
+
   // Common
   common: {
     loading: 'Loading...',
@@ -142,7 +185,20 @@ export default {
     accountCreatedSuccess: 'Account created successfully! Welcome to {siteName}.',
     turnstileExpired: 'Verification expired, please try again',
     turnstileFailed: 'Verification failed, please try again',
-    completeVerification: 'Please complete the verification'
+    completeVerification: 'Please complete the verification',
+    verifyYourEmail: 'Verify Your Email',
+    sessionExpired: 'Session expired',
+    sessionExpiredDesc: 'Please go back to the registration page and start again.',
+    verificationCode: 'Verification Code',
+    verificationCodeHint: 'Enter the 6-digit code sent to your email',
+    sendingCode: 'Sending...',
+    clickToResend: 'Click to resend code',
+    resendCode: 'Resend verification code',
+    oauth: {
+      code: 'Code',
+      state: 'State',
+      fullUrl: 'Full URL'
+    }
   },
 
   // Dashboard
@@ -377,6 +433,12 @@ export default {
     noData: 'No data found'
   },
 
+  // Table
+  table: {
+    expandActions: 'Expand More Actions',
+    collapseActions: 'Collapse Actions'
+  },
+
   // Pagination
   pagination: {
     showing: 'Showing',
@@ -584,6 +646,7 @@ export default {
         actions: 'Actions',
         billingType: 'Billing Type'
       },
+      rateAndAccounts: '{rate}x rate · {count} accounts',
       accountsCount: '{count} accounts',
       form: {
         name: 'Name',
@@ -742,6 +805,13 @@ export default {
         openai: 'OpenAI',
         gemini: 'Gemini'
       },
+      types: {
+        oauth: 'OAuth',
+        chatgptOauth: 'ChatGPT OAuth',
+        responsesApi: 'Responses API',
+        googleOauth: 'Google OAuth',
+        codeAssist: 'Code Assist'
+      },
       columns: {
         name: 'Name',
         platformType: 'Platform/Type',
@@ -1022,6 +1092,7 @@ export default {
         todayOverview: 'Today Overview',
         cost: 'Cost',
         requests: 'Requests',
+        tokens: 'Tokens',
         highestCostDay: 'Highest Cost Day',
         highestRequestDay: 'Highest Request Day',
         date: 'Date',
@@ -1037,6 +1108,9 @@ export default {
         todayCost: 'Today Cost',
         usageTrend: '30-Day Cost & Request Trend',
         noData: 'No usage data available for this account'
+      },
+      usageWindow: {
+        statsTitle: '5-Hour Window Usage Statistics'
       }
     },
 
@@ -1070,6 +1144,10 @@ export default {
       enterProxyName: 'Enter proxy name',
       leaveEmptyToKeep: 'Leave empty to keep current',
       optionalAuth: 'Optional authentication',
+      form: {
+        hostPlaceholder: 'proxy.example.com',
+        portPlaceholder: '8080'
+      },
       noProxiesYet: 'No proxies yet',
       createFirstProxy: 'Create your first proxy to route traffic through it.',
       // Batch import
@@ -1174,6 +1252,18 @@ export default {
       searchUserPlaceholder: 'Search user by email...',
       selectedUser: 'Selected',
       user: 'User',
+      account: 'Account',
+      group: 'Group',
+      requestId: 'Request ID',
+      allModels: 'All Models',
+      allAccounts: 'All Accounts',
+      allGroups: 'All Groups',
+      allTypes: 'All Types',
+      allBillingTypes: 'All Billing',
+      inputCost: 'Input Cost',
+      outputCost: 'Output Cost',
+      cacheCreationCost: 'Cache Creation Cost',
+      cacheReadCost: 'Cache Read Cost',
       failedToLoad: 'Failed to load usage records'
     },
 
@@ -1211,16 +1301,20 @@ export default {
         title: 'Site Settings',
         description: 'Customize site branding',
         siteName: 'Site Name',
+        siteNamePlaceholder: 'Sub2API',
         siteNameHint: 'Displayed in emails and page titles',
         siteSubtitle: 'Site Subtitle',
+        siteSubtitlePlaceholder: 'Subscription to API Conversion Platform',
         siteSubtitleHint: 'Displayed on login and register pages',
         apiBaseUrl: 'API Base URL',
+        apiBaseUrlPlaceholder: 'https://api.example.com',
         apiBaseUrlHint:
           'Used for "Use Key" and "Import to CC Switch" features. Leave empty to use current site URL.',
         contactInfo: 'Contact Info',
         contactInfoPlaceholder: 'e.g., QQ: 123456789',
         contactInfoHint: 'Customer support contact info, displayed on redeem page, profile, etc.',
         docUrl: 'Documentation URL',
+        docUrlPlaceholder: 'https://docs.example.com',
         docUrlHint: 'Link to your documentation site. Leave empty to hide the documentation link.',
         siteLogo: 'Site Logo',
         uploadImage: 'Upload Image',
@@ -1236,12 +1330,18 @@ export default {
         testConnection: 'Test Connection',
         testing: 'Testing...',
         host: 'SMTP Host',
+        hostPlaceholder: 'smtp.gmail.com',
         port: 'SMTP Port',
+        portPlaceholder: '587',
         username: 'SMTP Username',
+        usernamePlaceholder: 'your-email@gmail.com',
         password: 'SMTP Password',
+        passwordPlaceholder: '********',
         passwordHint: 'Leave empty to keep existing password',
         fromEmail: 'From Email',
+        fromEmailPlaceholder: 'noreply@example.com',
         fromName: 'From Name',
+        fromNamePlaceholder: 'Sub2API',
         useTls: 'Use TLS',
         useTlsHint: 'Enable TLS encryption for SMTP connection'
       },
@@ -1249,6 +1349,7 @@ export default {
         title: 'Send Test Email',
         description: 'Send a test email to verify your SMTP configuration',
         recipientEmail: 'Recipient Email',
+        recipientEmailPlaceholder: 'test@example.com',
         sendTestEmail: 'Send Test Email',
         sending: 'Sending...',
         enterRecipientHint: 'Please enter a recipient email address'