Fix(logger): preserve queued logs on shutdown; record exit signal

macos/main.mm

@@ -604,9 +604,13 @@ static void fillLoginInfo(LOGIN_INFOR& info)
 
 // ============== Signal Handling ==============
 
+// 注意：signal handler 内不能调 NSLog/Mprintf（NSLog 走 Foundation 锁，
+// Mprintf 走 Logger mutex/condvar），都不是 async-signal-safe。只在这里
+// 记 sig_atomic_t 标志位，main 退出循环后再补一行日志。
+static volatile sig_atomic_t g_lastSignal = 0;
 static void signalHandler(int sig)
 {
-    NSLog(@"Received signal %d, shutting down...", sig);
+    g_lastSignal = sig;
     g_running = false;
     g_bExit = S_CLIENT_EXIT;  // 通知所有工作线程退出
 }
@@ -934,6 +938,14 @@ int main(int argc, const char* argv[])
             }
         }
 
+        // 退出原因留痕：signal handler 不能直接打日志，在这里补一行。
+        if (g_lastSignal != 0) {
+            Mprintf(">>> Exit by signal %d (g_bExit=%d)\n",
+                    (int)g_lastSignal, (int)g_bExit);
+        } else {
+            Mprintf(">>> Exit normally (g_bExit=%d)\n", (int)g_bExit);
+        }
+
         NSLog(@"Shutting down...");
 
         // Release power assertions
@@ -944,6 +956,10 @@ int main(int argc, const char* argv[])
         // Display assertion is managed by ScreenHandler (released in stop())
         // powerActivity is automatically released when exiting @autoreleasepool
         (void)powerActivity;  // Suppress unused variable warning
+
+        // 显式停止日志，确保上面 Mprintf 的退出原因落盘。
+        // 不依赖 ~Logger() 的静态析构次序，避免后续新增日志相关静态对象时踩坑。
+        Logger::getInstance().stop();
     }
 
     return 0;