fix: resolve memory leaks and crash in macOS camera and screen capture

client/internal/screen/screen_darwin.go

@@ -63,6 +63,7 @@ static unsigned char* CaptureFullDesktop(int* outLen, int quality) {
         NSData *jpegData = [rep representationUsingType:NSBitmapImageFileTypeJPEG properties:props];
 
         if (!jpegData || jpegData.length == 0) {
+            [rep release];
             *outLen = 0;
             return NULL;
         }
@@ -70,6 +71,7 @@ static unsigned char* CaptureFullDesktop(int* outLen, int quality) {
         *outLen = (int)jpegData.length;
         unsigned char *buf = (unsigned char*)malloc(jpegData.length);
         memcpy(buf, jpegData.bytes, jpegData.length);
+        [rep release];
         return buf;
     }
 }