Add Tankri (Takri) Script Support — Himachal Pradesh Indigenous Script

## What is Tankri?

Tankri (Takri) is the indigenous script of Himachal Pradesh, India. Used for 400+ years to write administrative, religious, and literary documents across the Western Himalayan region.

- Unicode Block: U+11680-U+116CF (added Unicode 6.1, 2012)
- Script type: Abugida (Brahmic family)
- Region: Himachal Pradesh, J&K, Punjab Hills
- Speakers: ~20 million Pahari speakers
- ISO codes: bhd (Bhadrawahi), kfx (Kullu Pahari)

## Current Status

- Noto Sans Takri already exists on Google Fonts (86 characters)
- No bold, italic, or variable font weight available
- No ligature or conjunct support in current font
- Active revival: workshops at Sardar Patel University Mandi (2026)
- Keyman keyboard submitted: https://github.com/keymanapp/keyboards/pull/3982

## Request

1. Ensure Noto Sans Takri renders properly across all Android/Chrome versions
2. Add bold and italic variants to Noto Sans Takri
3. Add Tankri to Android system font fallback chain
4. Support Tankri rendering in Chrome, Gmail, Google Docs

## References

- Unicode Chart: https://unicode.org/charts/nameslist/n_11680.html
- Wikipedia: https://en.wikipedia.org/wiki/Takri_script
- Active platform: https://tankri.vercel.app