Opt-in watch folder on the batch queue: pick a directory once and new videos are auto-enqueued with the last Add-to-queue settings, with pause/stop controls and copy-in-progress protection. Files stream to the loopback backend as bytes; paths never leave the app. Also gives the batch queue a reachable UI entry point and streams multipart uploads to disk. Maintainer fix: the watched directory handle is opened with full share mode on Windows so users can rename or delete the folder while it is watched, matching macOS/Linux behaviour, with a cross-platform regression test. Thanks @mvanhorn!