feat: add Anek Bangla font for Bengali text

[TheTahsinShahriar]

Summary

Adds Anek Bangla (self-hosted variable font) for Bengali text rendering, sourced from the Fontsource package.

Changes

• resources/fonts/anek-bangla-bengali.woff2 - full variable font (weight 100-800, width axes), Bengali subset only
• resources/css/app.css - declares @font-face for Anek Bangla with unicode-range targeting Bengali glyphs, adds it to the font-sans stack after Instrument Sans, and applies font-stretch: 96% globally (fixed width for all Bengali text; weight varies per placement)

How it works

• Latin text -> Instrument Sans (first match in the stack)
• Bengali glyphs -> Anek Bangla (fallback, triggered by unicode-range)
• Width is fixed at 96 via font-stretch: 96% on body
• Weight is variable (100-800) and responds to Tailwind font-weight utilities (font-bold, font-semibold, etc.)

Notes

This PR is based on the chore/windows-dev-compatability-fix branch (PR #113). Once #113 merges, this PR becomes fonts-only.

[TheTahsinShahriar]

Superseded by #115 (clean branch off main)