Add Thorium User-Agent (UA) Branding

[gentrydeng]

Is your feature request related to a problem? Please describe.
Currently Thorium's User-Agent is the default Chromium UA without any self-identification.
I think it makes sense for more sites to recognise Thorium correctly.
This also helps to distinguish between the Chromium baseline version, and the Thorium patch version.

Describe the solution you'd like, including relevant patches or source
Add Thorium branding to UA, for example:

HTTP User-Agent
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36 Thorium/128.0.0.0

Sec-CH-UA
"Not;A=Brand";v="24", "Chromium";v="128", "Thorium";v="128"

Sec-CH-UA-Full-Version-List
"Not;A=Brand";v="24.0.0.0", "Chromium";v="128.0.6613.0", "Thorium";v="128.0.6613.189"

Did you read the FAQ?
Yes