feat(rate-limit): 实现分层 RPM 限速，支持系统默认/用户/独立Key三级配置

- 新增用户级 rate_limit 字段，支持系统默认/用户自定义/不限制三种模式
- 独立 Key 的 rate_limit 语义调整：null=跟随系统默认，0=不限制，>0=自定义
- 实现 UserRpmLimiter 基于 Redis sliding window 的 RPM 限速引擎
- Pipeline 请求流程集成用户级 RPM 检查
- 管理后台和用户面板新增 RPM 限速配置与实时状态查看
- 系统设置新增全局默认 RPM 配置项
- 迁移脚本回填现有 API Key 的 rate_limit 默认值
- 新增用户/Key RPM 状态监控 API 和前端展示

Closes #231

Co-authored-by: LewisPen <[email protected]>

frontend/src/views/admin/ApiKeys.vue

@@ -105,8 +105,8 @@
                 <TableHead class="w-[240px] h-12 font-semibold">
                   钱包
                 </TableHead>
-                <TableHead class="w-[130px] h-12 font-semibold">
-                  使用统计
+                <TableHead class="w-[190px] h-12 font-semibold">
+                  统计/限速
                 </TableHead>
                 <TableHead class="w-[110px] h-12 font-semibold">
                   有效期
@@ -221,7 +221,23 @@
                       请求: <span class="font-medium text-foreground">{{ (apiKey.total_requests || 0).toLocaleString() }}</span>
                     </div>
                     <div class="text-muted-foreground">
-                      速率: <span class="font-medium text-foreground">{{ apiKey.rate_limit ? `${apiKey.rate_limit}/min` : '未设置' }}</span>
+                      Tokens: <span class="font-medium text-foreground">{{ formatTokens(apiKey.total_tokens || 0) }}</span>
+                    </div>
+                    <div class="flex items-center gap-1 text-muted-foreground">
+                      <span>限速:</span>
+                      <Badge
+                        v-if="isRateLimitInherited(apiKey.rate_limit) || isRateLimitUnlimited(apiKey.rate_limit)"
+                        variant="secondary"
+                        class="h-5 px-1.5 py-0 text-[10px] font-medium"
+                      >
+                        {{ formatRateLimitInheritable(apiKey.rate_limit) }}
+                      </Badge>
+                      <span
+                        v-else
+                        class="font-medium text-foreground"
+                      >
+                        {{ formatRateLimitInheritable(apiKey.rate_limit) }}
+                      </span>
                     </div>
                   </div>
                 </TableCell>
@@ -387,6 +403,12 @@
                   >
                     {{ walletStatusLabel(getApiKeyWalletStatus(apiKey.id)) }}
                   </Badge>
+                  <Badge
+                    variant="secondary"
+                    class="h-5 px-1.5 py-0 text-[10px] font-medium"
+                  >
+                    {{ formatRateLimitInheritable(apiKey.rate_limit) }}
+                  </Badge>
                   <Badge
                     v-if="apiKey.auto_delete_on_expiry"
                     variant="secondary"
@@ -429,14 +451,6 @@
                 </div>
 
                 <div class="grid grid-cols-2 gap-2.5 text-xs">
-                  <div class="rounded-lg border border-border/50 bg-background/70 p-2.5">
-                    <div class="mb-1 text-muted-foreground">
-                      速率限制
-                    </div>
-                    <div class="font-semibold text-foreground">
-                      {{ apiKey.rate_limit ? `${apiKey.rate_limit}/min` : '未设置' }}
-                    </div>
-                  </div>
                   <div class="rounded-lg border border-border/50 bg-background/70 p-2.5">
                     <div class="mb-1 text-muted-foreground">
                       请求次数
@@ -445,6 +459,14 @@
                       {{ (apiKey.total_requests || 0).toLocaleString() }}
                     </div>
                   </div>
+                  <div class="rounded-lg border border-border/50 bg-background/70 p-2.5">
+                    <div class="mb-1 text-muted-foreground">
+                      Tokens
+                    </div>
+                    <div class="font-semibold text-foreground">
+                      {{ formatTokens(apiKey.total_tokens || 0) }}
+                    </div>
+                  </div>
                   <div class="col-span-2 rounded-lg border border-border/50 bg-background/70 p-2.5">
                     <div class="mb-1 text-muted-foreground">
                       有效期
@@ -663,6 +685,7 @@ import {
 
 import { StandaloneKeyFormDialog, type StandaloneKeyFormData } from '@/features/api-keys'
 import { parseApiError } from '@/utils/errorParser'
+import { formatTokens, formatRateLimitInheritable, isRateLimitInherited, isRateLimitUnlimited } from '@/utils/format'
 import { log } from '@/utils/logger'
 
 const { success, error } = useToast()
@@ -1028,7 +1051,7 @@ async function handleKeyFormSubmit(data: StandaloneKeyFormData) {
       const updateData: Partial<CreateStandaloneApiKeyRequest> = {
         name: data.name || undefined,
         unlimited_balance: Boolean(data.unlimited_balance),
-        rate_limit: data.rate_limit ?? null,  // undefined = 无限制，显式传 null
+        rate_limit: data.rate_limit ?? null,  // undefined = 跟随系统默认，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
@@ -1057,7 +1080,7 @@ async function handleKeyFormSubmit(data: StandaloneKeyFormData) {
       const createData: CreateStandaloneApiKeyRequest = {
         name: data.name || undefined,
         initial_balance_usd: isUnlimited ? null : (data.initial_balance_usd as number),
-        rate_limit: data.rate_limit ?? null,  // undefined = 无限制，显式传 null
+        rate_limit: data.rate_limit ?? null,  // undefined = 跟随系统默认，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