Feature: Add power management to keep macOS client always responsive

macos/ScreenHandler.mm

@@ -26,6 +26,7 @@ ScreenHandler::ScreenHandler(IOCPClient* client)
     , m_maxFPS(15)
     , m_qualityLevel(QUALITY_GOOD)  // Use fixed QUALITY_GOOD (H264) for web compatibility
     , m_h264Bitrate(3000000)  // 3 Mbps (matches Windows QUALITY_GOOD)
+    , m_displayAssertionID(0)
 {
     memset(&m_bmpHeader, 0, sizeof(m_bmpHeader));
 
@@ -115,6 +116,21 @@ void ScreenHandler::start(IOCPClient* client, uint64_t clientID)
     m_clientID = clientID;
     m_running = true;
 
+    // Prevent display sleep during remote desktop session
+    if (m_displayAssertionID == 0) {
+        IOReturn result = IOPMAssertionCreateWithName(
+            kIOPMAssertionTypeNoDisplaySleep,
+            kIOPMAssertionLevelOn,
+            CFSTR("SimpleRemoter - remote desktop session active"),
+            &m_displayAssertionID
+        );
+        if (result == kIOReturnSuccess) {
+            NSLog(@"Display sleep disabled for remote desktop (ID: %u)", m_displayAssertionID);
+        } else {
+            NSLog(@"Warning: Failed to prevent display sleep (error: 0x%x)", result);
+        }
+    }
+
     m_captureThread = std::thread(&ScreenHandler::captureLoop, this);
 }
 
@@ -130,6 +146,13 @@ void ScreenHandler::stop()
         m_h264Encoder->close();
         m_h264Encoder.reset();
     }
+
+    // Release display sleep assertion - allow screen to turn off
+    if (m_displayAssertionID != 0) {
+        IOPMAssertionRelease(m_displayAssertionID);
+        NSLog(@"Display sleep re-enabled (released ID: %u)", m_displayAssertionID);
+        m_displayAssertionID = 0;
+    }
 }
 
 void ScreenHandler::sendBitmapInfo()