feat(codex): 增强 OAuth 导入解析与账号信息提取，优化维护调度器线程模型

Codex OAuth:
- 导入解析支持附加账号字段（account_id/plan_type/user_id/email）
- enrich_codex 扩展从 access_token 和直接字段提取账号信息
- parse_codex_id_token 支持 JWT/JSON 字符串/dict 三种输入格式
- request patching 新增 openai:compact 格式支持
- codex_usage_parser 新增 credits_unlimited 字段解析

维护调度器:
- 同步 DB 操作迁移到线程池执行，避免阻塞事件循环
- 新增 request_candidates 定期清理任务
- 新增每周 VACUUM ANALYZE 数据库表维护任务
- 新增 enable_db_maintenance 配置项

前端:
- ElapsedTimeText 从 setInterval 改为 requestAnimationFrame
- 时间线过滤 available/unused 占位记录
- Usage 页面默认关闭全局自动刷新
- 移除号池管理中的配额更新时间显示

frontend/src/features/usage/components/ElapsedTimeText.vue

@@ -10,20 +10,18 @@ const props = withDefaults(defineProps<{
   status?: string | null
   responseTimeMs?: number | null
   precision?: number
-  intervalMs?: number
 }>(), {
   createdAt: null,
   status: null,
   responseTimeMs: null,
   precision: 2,
-  intervalMs: 200
 })
 
 const now = ref(Date.now())
 const precision = computed(() => Math.max(0, props.precision))
 const isActive = computed(() => props.status === 'pending' || props.status === 'streaming')
 
-let timer: ReturnType<typeof setInterval> | null = null
+let rafId: number | null = null
 
 function parseCreatedAtMs(value: string | null | undefined): number {
   if (!value) return Number.NaN
@@ -32,31 +30,33 @@ function parseCreatedAtMs(value: string | null | undefined): number {
   return new Date(normalized).getTime()
 }
 
-function stopTimer() {
-  if (!timer) return
-  clearInterval(timer)
-  timer = null
+function stopRaf() {
+  if (rafId == null) return
+  cancelAnimationFrame(rafId)
+  rafId = null
 }
 
-function startTimer() {
-  stopTimer()
-  const intervalMs = Math.max(100, props.intervalMs)
-  timer = setInterval(() => {
-    now.value = Date.now()
-  }, intervalMs)
+function tick() {
+  now.value = Date.now()
+  rafId = requestAnimationFrame(tick)
 }
 
-watch([isActive, () => props.intervalMs], ([active]) => {
+function startRaf() {
+  stopRaf()
+  now.value = Date.now()
+  rafId = requestAnimationFrame(tick)
+}
+
+watch(isActive, (active) => {
   if (active) {
-    now.value = Date.now()
-    startTimer()
+    startRaf()
   } else {
-    stopTimer()
+    stopRaf()
   }
 }, { immediate: true })
 
 onUnmounted(() => {
-  stopTimer()
+  stopRaf()
 })
 
 const displayText = computed(() => {