feat(queue): 优化用户消息队列锁释放时机

将队列锁释放时机从"请求完成后"提前到"请求发送后"，因为 Claude API
限流（RPM）基于请求发送时刻计算，无需等待响应完成。

主要变更：
- 移除锁续租机制（startLockRenewal、refreshUserMessageLock）
- 所有 relay 服务在请求发送成功后立即释放锁
- 流式请求通过 onResponseStart 回调在收到响应头时释放
- 调整默认配置：timeoutMs 60s→5s，lockTtlMs 120s→5s
- 新增 USER_MESSAGE_QUEUE_LOCK_TTL_MS 环境变量支持

src/services/ccrRelayService.js

@@ -24,7 +24,6 @@ class CcrRelayService {
     let account = null
     let queueLockAcquired = false
     let queueRequestId = null
-    let queueLockRenewalStopper = null
 
     try {
       // 📬 用户消息队列处理
@@ -78,9 +77,8 @@ class CcrRelayService {
         if (queueResult.acquired && !queueResult.skipped) {
           queueLockAcquired = true
           queueRequestId = queueResult.requestId
-          queueLockRenewalStopper = await userMessageQueueService.startLockRenewal(
-            accountId,
-            queueRequestId
+          logger.debug(
+            `📬 User message queue lock acquired for CCR account ${accountId}, requestId: ${queueRequestId}`
           )
         }
       }
@@ -224,6 +222,23 @@ class CcrRelayService {
       )
       const response = await axios(requestConfig)
 
+      // 📬 请求已发送成功，立即释放队列锁（无需等待响应处理完成）
+      // 因为 Claude API 限流基于请求发送时刻计算（RPM），不是请求完成时刻
+      if (queueLockAcquired && queueRequestId && accountId) {
+        try {
+          await userMessageQueueService.releaseQueueLock(accountId, queueRequestId)
+          queueLockAcquired = false // 标记已释放，防止 finally 重复释放
+          logger.debug(
+            `📬 User message queue lock released early for CCR account ${accountId}, requestId: ${queueRequestId}`
+          )
+        } catch (releaseError) {
+          logger.error(
+            `❌ Failed to release user message queue lock early for CCR account ${accountId}:`,
+            releaseError.message
+          )
+        }
+      }
+
       // 移除监听器（请求成功完成）
       if (clientRequest) {
         clientRequest.removeListener('close', handleClientDisconnect)
@@ -296,13 +311,13 @@ class CcrRelayService {
 
       throw error
     } finally {
-      // 📬 释放用户消息队列锁
+      // 📬 释放用户消息队列锁（兜底，正常情况下已在请求发送后提前释放）
       if (queueLockAcquired && queueRequestId && accountId) {
         try {
-          if (queueLockRenewalStopper) {
-            queueLockRenewalStopper()
-          }
           await userMessageQueueService.releaseQueueLock(accountId, queueRequestId)
+          logger.debug(
+            `📬 User message queue lock released in finally for CCR account ${accountId}, requestId: ${queueRequestId}`
+          )
         } catch (releaseError) {
           logger.error(
             `❌ Failed to release user message queue lock for CCR account ${accountId}:`,
@@ -327,7 +342,6 @@ class CcrRelayService {
     let account = null
     let queueLockAcquired = false
     let queueRequestId = null
-    let queueLockRenewalStopper = null
 
     try {
       // 📬 用户消息队列处理
@@ -388,9 +402,8 @@ class CcrRelayService {
         if (queueResult.acquired && !queueResult.skipped) {
           queueLockAcquired = true
           queueRequestId = queueResult.requestId
-          queueLockRenewalStopper = await userMessageQueueService.startLockRenewal(
-            accountId,
-            queueRequestId
+          logger.debug(
+            `📬 User message queue lock acquired for CCR account ${accountId} (stream), requestId: ${queueRequestId}`
           )
         }
       }
@@ -442,7 +455,24 @@ class CcrRelayService {
         accountId,
         usageCallback,
         streamTransformer,
-        options
+        options,
+        // 📬 回调：在收到响应头时释放队列锁
+        async () => {
+          if (queueLockAcquired && queueRequestId && accountId) {
+            try {
+              await userMessageQueueService.releaseQueueLock(accountId, queueRequestId)
+              queueLockAcquired = false // 标记已释放，防止 finally 重复释放
+              logger.debug(
+                `📬 User message queue lock released early for CCR stream account ${accountId}, requestId: ${queueRequestId}`
+              )
+            } catch (releaseError) {
+              logger.error(
+                `❌ Failed to release user message queue lock early for CCR stream account ${accountId}:`,
+                releaseError.message
+              )
+            }
+          }
+        }
       )
 
       // 更新最后使用时间
@@ -451,13 +481,13 @@ class CcrRelayService {
       logger.error(`❌ CCR stream relay failed (Account: ${account?.name || accountId}):`, error)
       throw error
     } finally {
-      // 📬 释放用户消息队列锁
+      // 📬 释放用户消息队列锁（兜底，正常情况下已在收到响应头后提前释放）
       if (queueLockAcquired && queueRequestId && accountId) {
         try {
-          if (queueLockRenewalStopper) {
-            queueLockRenewalStopper()
-          }
           await userMessageQueueService.releaseQueueLock(accountId, queueRequestId)
+          logger.debug(
+            `📬 User message queue lock released in finally for CCR stream account ${accountId}, requestId: ${queueRequestId}`
+          )
         } catch (releaseError) {
           logger.error(
             `❌ Failed to release user message queue lock for CCR stream account ${accountId}:`,
@@ -478,7 +508,8 @@ class CcrRelayService {
     accountId,
     usageCallback,
     streamTransformer = null,
-    requestOptions = {}
+    requestOptions = {},
+    onResponseHeaderReceived = null
   ) {
     return new Promise((resolve, reject) => {
       let aborted = false
@@ -541,8 +572,11 @@ class CcrRelayService {
       // 发送请求
       const request = axios(requestConfig)
 
+      // 注意：使用 .then(async ...) 模式处理响应
+      // - 内部的 releaseQueueLock 有独立的 try-catch，不会导致未捕获异常
+      // - queueLockAcquired = false 的赋值会在 finally 执行前完成（JS 单线程保证）
       request
-        .then((response) => {
+        .then(async (response) => {
           logger.debug(`🌊 CCR stream response status: ${response.status}`)
 
           // 错误响应处理
@@ -592,6 +626,19 @@ class CcrRelayService {
             return
           }
 
+          // 📬 收到成功响应头（HTTP 200），调用回调释放队列锁
+          // 此时请求已被 Claude API 接受并计入 RPM 配额，无需等待响应完成
+          if (onResponseHeaderReceived && typeof onResponseHeaderReceived === 'function') {
+            try {
+              await onResponseHeaderReceived()
+            } catch (callbackError) {
+              logger.error(
+                `❌ Failed to execute onResponseHeaderReceived callback for CCR stream account ${accountId}:`,
+                callbackError.message
+              )
+            }
+          }
+
           // 成功响应，检查并移除错误状态
           ccrAccountService.isAccountRateLimited(accountId).then((isRateLimited) => {
             if (isRateLimited) {