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/views/admin/RedeemView.vue

@@ -9,19 +9,7 @@
           class="btn btn-secondary"
           :title="t('common.refresh')"
         >
-          <svg
-            :class="['h-5 w-5', loading ? 'animate-spin' : '']"
-            fill="none"
-            viewBox="0 0 24 24"
-            stroke="currentColor"
-            stroke-width="1.5"
-          >
-            <path
-              stroke-linecap="round"
-              stroke-linejoin="round"
-              d="M16.023 9.348h4.992v-.001M2.985 19.644v-4.992m0 0h4.992m-4.993 0l3.181 3.183a8.25 8.25 0 0013.803-3.7M4.031 9.865a8.25 8.25 0 0113.803-3.7l3.181 3.182m0-4.991v4.99"
-            />
-          </svg>
+          <Icon name="refresh" size="md" :class="loading ? 'animate-spin' : ''" />
         </button>
         <button @click="showGenerateDialog = true" class="btn btn-primary">
           {{ t('admin.redeem.generateCodes') }}
@@ -75,20 +63,7 @@
                 ]"
                 :title="copiedCode === value ? t('admin.redeem.copied') : t('keys.copyToClipboard')"
               >
-                <svg
-                  v-if="copiedCode !== value"
-                  class="h-4 w-4"
-                  fill="none"
-                  stroke="currentColor"
-                  viewBox="0 0 24 24"
-                >
-                  <path
-                    stroke-linecap="round"
-                    stroke-linejoin="round"
-                    stroke-width="2"
-                    d="M8 16H6a2 2 0 01-2-2V6a2 2 0 012-2h8a2 2 0 012 2v2m-6 12h8a2 2 0 002-2v-8a2 2 0 00-2-2h-8a2 2 0 00-2 2v8a2 2 0 002 2z"
-                  />
-                </svg>
+                <Icon v-if="copiedCode !== value" name="copy" size="sm" :stroke-width="2" />
                 <svg v-else class="h-4 w-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                   <path
                     stroke-linecap="round"
@@ -341,14 +316,7 @@
               @click="closeResultDialog"
               class="rounded-lg p-1.5 text-gray-400 transition-colors hover:bg-gray-100 hover:text-gray-600 dark:hover:bg-dark-700 dark:hover:text-gray-300"
             >
-              <svg class="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path
-                  stroke-linecap="round"
-                  stroke-linejoin="round"
-                  stroke-width="2"
-                  d="M6 18L18 6M6 6l12 12"
-                />
-              </svg>
+              <Icon name="x" size="md" :stroke-width="2" />
             </button>
           </div>
           <!-- Content -->
@@ -373,20 +341,7 @@
                 copiedAll ? 'btn-success' : 'btn-secondary'
               ]"
             >
-              <svg
-                v-if="!copiedAll"
-                class="h-4 w-4"
-                fill="none"
-                stroke="currentColor"
-                viewBox="0 0 24 24"
-              >
-                <path
-                  stroke-linecap="round"
-                  stroke-linejoin="round"
-                  stroke-width="2"
-                  d="M8 16H6a2 2 0 01-2-2V6a2 2 0 012-2h8a2 2 0 012 2v2m-6 12h8a2 2 0 002-2v-8a2 2 0 00-2-2h-8a2 2 0 00-2 2v8a2 2 0 002 2z"
-                />
-              </svg>
+              <Icon v-if="!copiedAll" name="copy" size="sm" :stroke-width="2" />
               <svg v-else class="h-4 w-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                 <path
                   stroke-linecap="round"
@@ -398,14 +353,7 @@
               {{ copiedAll ? t('admin.redeem.copied') : t('admin.redeem.copyAll') }}
             </button>
             <button @click="downloadGeneratedCodes" class="btn btn-primary flex items-center gap-2">
-              <svg class="h-4 w-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path
-                  stroke-linecap="round"
-                  stroke-linejoin="round"
-                  stroke-width="2"
-                  d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4"
-                />
-              </svg>
+              <Icon name="download" size="sm" :stroke-width="2" />
               {{ t('admin.redeem.download') }}
             </button>
           </div>
@@ -430,6 +378,7 @@ import DataTable from '@/components/common/DataTable.vue'
 import Pagination from '@/components/common/Pagination.vue'
 import ConfirmDialog from '@/components/common/ConfirmDialog.vue'
 import Select from '@/components/common/Select.vue'
+import Icon from '@/components/icons/Icon.vue'
 
 const { t } = useI18n()
 const appStore = useAppStore()