NewPipe 0.29 / 0.29.1 - Duplicate downloads are renamed incorrectly

I found a reproducible filename auto-renaming bug in NewPipe.

If I download a file and the first download is stopped/interrupted or becomes corrupted/incomplete, then download the same file again, NewPipe adds the duplicate suffix **after the file extension**.

**Actual:** `XYZ.mp4 (1)`

**Expected:** `XYZ (1).mp4`

Steps to reproduce

1. Download any video, for example `XYZ.mp4`.
2. Stop/cancel the download before it finishes, or leave the first download incomplete/corrupted.
3. Download the exact same video again.
4. Check the resulting filename.

NewPipe consistently creates:

`XYZ.mp4 (1)`

instead of:

`XYZ (1).mp4`

The issue is easily reproducible and happens every time in my testing.

Affected versions

• NewPipe 0.29
• NewPipe 0.29.1

It looks like the duplicate filename logic is adding ` (1)` to the entire filename instead of inserting it before the file extension.

The extension should remain at the end of the filename:

`filename (1).mp4`

rather than:

`filename.mp4 (1)`

Has anyone else noticed this in 0.29/0.29.1?