refactor: API Key 过期时间改用日期选择器，rate_limit 支持无限制

- 前端：将过期时间设置从"天数输入"改为"日期选择器"，更直观
- 后端：新增 expires_at 字段（ISO 日期格式），兼容旧版 expire_days
- rate_limit 字段现在支持 null 表示无限制，移除默认值 100
- 解析逻辑：过期时间设为当天 UTC 23:59:59.999999

frontend/src/api/admin.ts

@@ -42,7 +42,7 @@ export interface UserApiKeyExport {
   allowed_endpoints?: string[] | null
   allowed_api_formats?: string[] | null
   allowed_models?: string[] | null
-  rate_limit?: number
+  rate_limit?: number | null  // null = 无限制
   concurrent_limit?: number | null
   force_capabilities?: any
   is_active: boolean
@@ -220,7 +220,7 @@ export interface AdminApiKey {
   total_requests?: number
   total_tokens?: number
   total_cost_usd?: number
-  rate_limit?: number
+  rate_limit?: number | null  // null = 无限制
   allowed_providers?: string[] | null  // 允许的提供商列表
   allowed_api_formats?: string[] | null  // 允许的 API 格式列表
   allowed_models?: string[] | null  // 允许的模型列表
@@ -236,8 +236,8 @@ export interface CreateStandaloneApiKeyRequest {
   allowed_providers?: string[] | null
   allowed_api_formats?: string[] | null
   allowed_models?: string[] | null
-  rate_limit?: number
-  expire_days?: number | null  // null = 永不过期
+  rate_limit?: number | null  // null = 无限制
+  expires_at?: string | null  // ISO 日期字符串，如 "2025-12-31"，null = 永不过期
   initial_balance_usd: number  // 初始余额，必须设置
   auto_delete_on_expiry?: boolean  // 过期后是否自动删除
 }

frontend/src/features/api-keys/components/StandaloneKeyFormDialog.vue

@@ -79,45 +79,45 @@
 
           <div class="space-y-2">
             <Label
-              for="form-expire-days"
+              for="form-expires-at"
               class="text-sm font-medium"
             >有效期设置</Label>
             <div class="flex items-center gap-2">
-              <Input
-                id="form-expire-days"
-                :model-value="form.expire_days ?? ''"
-                type="number"
-                min="1"
-                max="3650"
-                placeholder="天数"
-                :class="form.never_expire ? 'flex-1 h-9 opacity-50' : 'flex-1 h-9'"
-                :disabled="form.never_expire"
-                @update:model-value="(v) => form.expire_days = parseNumberInput(v, { min: 1, max: 3650 })"
-              />
-              <label class="flex items-center gap-1.5 border rounded-md px-2 py-1.5 bg-muted/50 cursor-pointer text-xs whitespace-nowrap">
-                <input
-                  v-model="form.never_expire"
-                  type="checkbox"
-                  class="h-3.5 w-3.5 rounded border-gray-300 cursor-pointer"
-                  @change="onNeverExpireChange"
+              <div class="relative flex-1">
+                <Input
+                  id="form-expires-at"
+                  :model-value="form.expires_at || ''"
+                  type="date"
+                  :min="minExpiryDate"
+                  class="h-9 pr-8"
+                  :placeholder="form.expires_at ? '' : '永不过期'"
+                  @update:model-value="(v) => form.expires_at = v || undefined"
+                />
+                <button
+                  v-if="form.expires_at"
+                  type="button"
+                  class="absolute right-2 top-1/2 -translate-y-1/2 text-muted-foreground hover:text-foreground"
+                  title="清空（永不过期）"
+                  @click="clearExpiryDate"
                 >
-                永不过期
-              </label>
+                  <X class="h-4 w-4" />
+                </button>
+              </div>
               <label
                 class="flex items-center gap-1.5 border rounded-md px-2 py-1.5 bg-muted/50 cursor-pointer text-xs whitespace-nowrap"
-                :class="form.never_expire ? 'opacity-50' : ''"
+                :class="!form.expires_at ? 'opacity-50 cursor-not-allowed' : ''"
               >
                 <input
                   v-model="form.auto_delete_on_expiry"
                   type="checkbox"
                   class="h-3.5 w-3.5 rounded border-gray-300 cursor-pointer"
-                  :disabled="form.never_expire"
+                  :disabled="!form.expires_at"
                 >
                 到期删除
               </label>
             </div>
             <p class="text-xs text-muted-foreground">
-              不勾选"到期删除"则仅禁用
+              {{ form.expires_at ? '到期后' + (form.auto_delete_on_expiry ? '自动删除' : '仅禁用') + '（当天 UTC 23:59 失效）' : '留空表示永不过期' }}
             </p>
           </div>
 
@@ -280,7 +280,7 @@ import {
   Input,
   Label,
 } from '@/components/ui'
-import { Plus, SquarePen, Key, Shield, ChevronDown } from 'lucide-vue-next'
+import { Plus, SquarePen, Key, Shield, ChevronDown, X } from 'lucide-vue-next'
 import { useFormDialog } from '@/composables/useFormDialog'
 import { ModelMultiSelect } from '@/components/common'
 import { getProvidersSummary } from '@/api/endpoints/providers'
@@ -294,8 +294,7 @@ export interface StandaloneKeyFormData {
   id?: string
   name: string
   initial_balance_usd?: number
-  expire_days?: number
-  never_expire: boolean
+  expires_at?: string  // ISO 日期字符串，如 "2025-12-31"，undefined = 永不过期
   rate_limit?: number
   auto_delete_on_expiry: boolean
   allowed_providers: string[]
@@ -329,8 +328,7 @@ const allApiFormats = ref<string[]>([])
 const form = ref<StandaloneKeyFormData>({
   name: '',
   initial_balance_usd: 10,
-  expire_days: undefined,
-  never_expire: true,
+  expires_at: undefined,
   rate_limit: undefined,
   auto_delete_on_expiry: false,
   allowed_providers: [],
@@ -338,12 +336,18 @@ const form = ref<StandaloneKeyFormData>({
   allowed_models: []
 })
 
+// 计算最小可选日期（明天）
+const minExpiryDate = computed(() => {
+  const tomorrow = new Date()
+  tomorrow.setDate(tomorrow.getDate() + 1)
+  return tomorrow.toISOString().split('T')[0]
+})
+
 function resetForm() {
   form.value = {
     name: '',
     initial_balance_usd: 10,
-    expire_days: undefined,
-    never_expire: true,
+    expires_at: undefined,
     rate_limit: undefined,
     auto_delete_on_expiry: false,
     allowed_providers: [],
@@ -360,8 +364,7 @@ function loadKeyData() {
     id: props.apiKey.id,
     name: props.apiKey.name || '',
     initial_balance_usd: props.apiKey.initial_balance_usd,
-    expire_days: props.apiKey.expire_days,
-    never_expire: props.apiKey.never_expire,
+    expires_at: props.apiKey.expires_at,
     rate_limit: props.apiKey.rate_limit,
     auto_delete_on_expiry: props.apiKey.auto_delete_on_expiry,
     allowed_providers: props.apiKey.allowed_providers || [],
@@ -406,12 +409,10 @@ function toggleSelection(field: 'allowed_providers' | 'allowed_api_formats' | 'a
   }
 }
 
-// 永不过期切换
-function onNeverExpireChange() {
-  if (form.value.never_expire) {
-    form.value.expire_days = undefined
-    form.value.auto_delete_on_expiry = false
-  }
+// 清空过期日期（同时清空到期删除选项）
+function clearExpiryDate() {
+  form.value.expires_at = undefined
+  form.value.auto_delete_on_expiry = false
 }
 
 // 提交表单

frontend/src/views/admin/ApiKeys.vue

@@ -850,28 +850,20 @@ async function deleteApiKey(apiKey: AdminApiKey) {
 }
 
 function editApiKey(apiKey: AdminApiKey) {
-  // 计算过期天数
-  let expireDays: number | undefined = undefined
-  let neverExpire = true
+  // 解析过期日期为 YYYY-MM-DD 格式
+  // 保留原始日期，不做时间过滤（避免编辑当天过期的 Key 时意外清空）
+  let expiresAt: string | undefined = undefined
 
   if (apiKey.expires_at) {
     const expiresDate = new Date(apiKey.expires_at)
-    const now = new Date()
-    const diffMs = expiresDate.getTime() - now.getTime()
-    const diffDays = Math.ceil(diffMs / (1000 * 60 * 60 * 24))
-
-    if (diffDays > 0) {
-      expireDays = diffDays
-      neverExpire = false
-    }
+    expiresAt = expiresDate.toISOString().split('T')[0]
   }
 
   editingKeyData.value = {
     id: apiKey.id,
     name: apiKey.name || '',
-    expire_days: expireDays,
-    never_expire: neverExpire,
-    rate_limit: apiKey.rate_limit || 100,
+    expires_at: expiresAt,
+    rate_limit: apiKey.rate_limit ?? undefined,
     auto_delete_on_expiry: apiKey.auto_delete_on_expiry || false,
     allowed_providers: apiKey.allowed_providers || [],
     allowed_api_formats: apiKey.allowed_api_formats || [],
@@ -1033,14 +1025,25 @@ function closeKeyFormDialog() {
 
 // 统一处理表单提交
 async function handleKeyFormSubmit(data: StandaloneKeyFormData) {
+  // 验证过期日期（如果设置了，必须晚于今天）
+  if (data.expires_at) {
+    const selectedDate = new Date(data.expires_at)
+    const today = new Date()
+    today.setHours(0, 0, 0, 0)
+    if (selectedDate <= today) {
+      error('过期日期必须晚于今天')
+      return
+    }
+  }
+
   keyFormDialogRef.value?.setSaving(true)
   try {
     if (data.id) {
       // 更新
       const updateData: Partial<CreateStandaloneApiKeyRequest> = {
         name: data.name || undefined,
-        rate_limit: data.rate_limit,
-        expire_days: data.never_expire ? null : (data.expire_days || null),
+        rate_limit: data.rate_limit ?? null,  // undefined = 无限制，显式传 null
+        expires_at: data.expires_at || null,  // undefined/空 = 永不过期
         auto_delete_on_expiry: data.auto_delete_on_expiry,
         // 空数组表示清除限制（允许全部），后端会将空数组存为 NULL
         allowed_providers: data.allowed_providers,
@@ -1058,8 +1061,8 @@ async function handleKeyFormSubmit(data: StandaloneKeyFormData) {
       const createData: CreateStandaloneApiKeyRequest = {
         name: data.name || undefined,
         initial_balance_usd: data.initial_balance_usd,
-        rate_limit: data.rate_limit,
-        expire_days: data.never_expire ? null : (data.expire_days || null),
+        rate_limit: data.rate_limit ?? null,  // undefined = 无限制，显式传 null
+        expires_at: data.expires_at || null,  // undefined/空 = 永不过期
         auto_delete_on_expiry: data.auto_delete_on_expiry,
         // 空数组表示不设置限制（允许全部），后端会将空数组存为 NULL
         allowed_providers: data.allowed_providers,