Add ThinWangT Joyig

**Font Project Git Repo URL:**
https://github.com/thinleywangchuk478/ThinWangT_Joyig

**Super short description of the Font Family:**
ThinWangT Joyig is an open-source Dzongkha/Tibetan
script typeface designed for the Kingdom of Bhutan.
It is optimized for readability at 18pt, supporting
the complex stacked characters of the Dzongkha script.
This font gives readers and writers real handwritten feelings.

This font fills a critical gap—Dzongkha is the
national language of Bhutan and is severely
underrepresented on Google Fonts.

**Requirements:**
- [x] The entire font project is available in a Github
repository and licensed under the OFL
- [x] The source files are available in the repo
- [x] I am the sole copyright author of the entire project
- [x] There are no Reserved Font Names in the OFL
- [x] The family name is unique according to namecheck.fontdata.com
- [x] The name of the font family is clearly communicated
and does not include copyright holder's full names
- [x] The font supports at least the Google Fonts Latin Core glyphset
- [x] The repo has the Google Fonts preferred upstream repo structure
- [x] I have read, agree with, and comply with, the full
Google Fonts contributing requirements
- [x] I will maintain the repository and participate
in the onboarding process

**Image:**
[Attach your specimen image here.]