refactor(frontend): 完成所有组件的内联SVG统一替换为Icon组件

- 扩展 Icon.vue 组件，新增 60+ 图标路径
  - 导航类: arrowRight, arrowLeft, arrowUp, arrowDown, chevronUp, externalLink
  - 状态类: checkCircle, xCircle, exclamationCircle, exclamationTriangle, infoCircle
  - 用户类: user, userCircle, userPlus, users
  - 文档类: document, clipboard, copy, inbox
  - 操作类: download, upload, filter, sort
  - 安全类: key, lock, shield
  - UI类: menu, calendar, home, terminal, gift, creditCard, mail
  - 数据类: chartBar, trendingUp, database, cube
  - 其他: bolt, sparkles, cloud, server, sun, moon, book 等

- 重构 56 个 Vue 组件，用 Icon 组件替换内联 SVG
  - 净减少约 2200 行代码
  - 提升代码可维护性和一致性
  - 统一图标样式和尺寸管理

frontend/src/components/keys/UseKeyModal.vue

@@ -81,9 +81,7 @@
           >
             <!-- File Hint (if exists) -->
             <p v-if="file.hint" class="text-xs text-amber-600 dark:text-amber-400 mb-1.5 flex items-center gap-1">
-              <svg class="w-3.5 h-3.5 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24" stroke-width="1.5">
-                <path stroke-linecap="round" stroke-linejoin="round" d="M12 9v3.75m9-.75a9 9 0 11-18 0 9 9 0 0118 0zm-9 3.75h.008v.008H12v-.008z" />
-              </svg>
+              <Icon name="exclamationCircle" size="sm" class="flex-shrink-0" />
               {{ file.hint }}
             </p>
             <div class="bg-gray-900 dark:bg-dark-900 rounded-xl overflow-hidden">
@@ -117,9 +115,7 @@
 
         <!-- Usage Note -->
         <div class="flex items-start gap-3 p-3 rounded-lg bg-blue-50 dark:bg-blue-900/20 border border-blue-100 dark:border-blue-800">
-          <svg class="w-5 h-5 text-blue-500 flex-shrink-0 mt-0.5" fill="none" stroke="currentColor" viewBox="0 0 24 24" stroke-width="1.5">
-            <path stroke-linecap="round" stroke-linejoin="round" d="M11.25 11.25l.041-.02a.75.75 0 011.063.852l-.708 2.836a.75.75 0 001.063.853l.041-.021M21 12a9 9 0 11-18 0 9 9 0 0118 0zm-9-3.75h.008v.008H12V8.25z" />
-          </svg>
+          <Icon name="infoCircle" size="md" class="text-blue-500 flex-shrink-0 mt-0.5" />
           <p class="text-sm text-blue-700 dark:text-blue-300">
             {{ platformNote }}
           </p>
@@ -144,6 +140,7 @@
 import { ref, computed, h, watch, type Component } from 'vue'
 import { useI18n } from 'vue-i18n'
 import BaseDialog from '@/components/common/BaseDialog.vue'
+import Icon from '@/components/icons/Icon.vue'
 import { useClipboard } from '@/composables/useClipboard'
 import type { GroupPlatform } from '@/types'