[Bug]: Chapter marker placement isnt correct

### Guidelines

- [x] I have encountered this bug in the [latest release of FreeTube](https://github.com/FreeTubeApp/FreeTube/releases).
- [x] I have encountered this bug in the [official downloads of FreeTube](https://github.com/FreeTubeApp/FreeTube#official-downloads). **The only official downloads are from the [https://freetubeapp.io](https://freetubeapp.io/#download) website, the [FreeTubeApp/FreeTube GitHub repository](https://github.com/FreeTubeApp/FreeTube/releases) and the [io.freetubeapp.FreeTube flatpak](https://flathub.org/en/apps/io.freetubeapp.FreeTube) from Flathub.**
- [x] I have [searched the issue tracker for **open and closed** issues](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aissue+sort%3Arelevance-desc) that are similar to the bug report I want to file, without success.
- [x] I have searched the [documentation](https://docs.freetubeapp.io/) for information that matches the description of the bug I want to file, without success.
- [x] This issue contains only one bug.
- [x] I have read and agree to follow the [rules](https://docs.freetubeapp.io/community/rules/).

### Describe the bug

1. Go to a video that has chapters, e.g. https://youtu.be/xMGrnPmc7ro
2. Check timestamp for a chapter in the description or in the chapters section
3. Locate that timestamp on seekbar
4. See that the marker of the chapter isnt correctly placed

### Expected Behavior

Chapter marked should be placed correctly

### Issue Labels

usability issue

### FreeTube Version

v0.25.1-nightly-7617 Beta

### Operating System Version

Windows 11 IoT Enterprise LTSC 24H2

### Installation Method

.exe

### Primary API used

Local API

### Last Known Working FreeTube Version (If Any)

_No response_

### Upload screenshots or videos

[FreeTube_y1ZT1JNjMy.mp4](https://github.com/user-attachments/assets/28cd8253-35b1-4355-be07-e813f7cf11a5)

### Additional Information

_No response_

### Nightly Build

- [x] I have encountered this bug in the latest **official** [nightly build](https://docs.freetubeapp.io/development/nightly-builds), do not check this box if you are using an unofficial or custom build.

Reproduce the issue using the linked video: compare a chapter timestamp in the description or chapters section with its marker on the seekbar. No source file, test, or entry point is named, so first trace the chapter-marker placement from the seekbar UI; done means the marker aligns with the chapter timestamp.

Written by the indexing model from the issue text.