perf: Redis 操作优化，移除号池 key 列表的 Usage 聚合查询

- 号池 key 列表移除 Usage 表聚合查询(total_tokens/total_cost_usd)，消除慢 SQL
- cooldown 计数从 SCAN 改为 SCARD (O(1))，通过 cooldown_idx SET 维护索引
- 读路径 Lua 脚本移除 ZREMRANGEBYSCORE，清理移至写路径减少开销
- affinity 清理从 KEYS 改为 SCAN 分批删除，invalidate_all_for_provider 改用 pipeline 批量 MGET+UNLINK
- 缓存监控页添加清除按钮 loading 状态，Redis SCAN 并发限制为 4
- 提取 redis_utils 模块统一 SCAN+批量删除逻辑
- 调度热路径跳过 cooldown TTL 查询，account_state 预计算移出循环

frontend/src/views/admin/CacheMonitoring.vue

@@ -44,6 +44,7 @@ const listLoading = ref(false)
 const tableKeyword = ref('')
 const matchedUserId = ref<string | null>(null)
 const clearingRowAffinityKey = ref<string | null>(null)
+const clearingAllAffinity = ref(false)
 const currentPage = ref(1)
 const pageSize = ref(20)
 const currentTime = ref(Math.floor(Date.now() / 1000))
@@ -203,6 +204,7 @@ async function clearAllCache() {
   })
   if (!secondConfirm) return
 
+  clearingAllAffinity.value = true
   try {
     await cacheApi.clearAllCache()
     showSuccess('已清除所有缓存')
@@ -211,6 +213,8 @@ async function clearAllCache() {
   } catch (error) {
     showError('清除失败')
     log.error('清除所有缓存失败', error)
+  } finally {
+    clearingAllAffinity.value = false
   }
 }
 
@@ -571,6 +575,7 @@ onBeforeUnmount(() => {
               variant="ghost"
               size="icon"
               class="h-8 w-8 text-muted-foreground/70 hover:text-destructive"
+              :disabled="clearingAllAffinity"
               title="清除全部缓存"
               @click="clearAllCache"
             >