Skip existing files can skip duplicate-title videos in the same batch

Version

prime branch / latest

Platform

Any

Steps to reproduce

• Turn on Skip existing files
• Queue a batch where two selected videos would save with the same filename
  • easiest case is two videos with the same title while using the default $title filename template
• Pick the download folder and confirm

Details

I think there is a small edge case in the way the app reserves filenames.

If Skip existing files is off, the app does the right thing and gives the second file a unique name, like:

Title.mp4
Title (1).mp4

But if Skip existing files is on, the second video can be skipped instead.

The reason seems to be that the first video creates a zero-byte placeholder file to reserve Title.mp4. Then, when the second video is checked, this line sees that placeholder and treats it like a real existing file:

if (settingsService.ShouldSkipExistingFiles && File.Exists(baseFilePath))
    continue;

At that point the app never gets to EnsureUniqueFilePath(...), so it does not try Title (1).mp4.

I think the skip check needs to ignore files that were only created as reservations during the current batch, or otherwise check for existing files before the batch starts.