[SteelCrab]

Summary

• Add a Font option to Terminal Settings to choose the terminal font family.
• The choice is persisted with the other settings and applied live to open terminals.
• Fira Code (bundled) stays the default; other fonts are used when installed locally, otherwise the existing monospace fallback stack applies.
• Includes Nerd Font variants so prompt icons (e.g. Starship) render instead of tofu boxes.

Test plan

• npm run lint, npm run build
• Switch fonts in a live session: terminals re-render immediately, including Nerd Font glyphs
• Invalid stored font value falls back to the default