Fix terminal link dialog layering

[ZacharyZcR]

Summary

• render the terminal link confirmation dialog through a body portal
• keep the existing terminal link behavior settings while avoiding clipping/stacking issues in embedded file-manager terminal windows

Verification

• npm run type-check
• npx eslint src/ui/features/terminal/Terminal.tsx
• npx prettier --check src/ui/features/terminal/Terminal.tsx
• git diff --check

Notes

• npm run build still fails before this change is reached because @fontsource/jetbrains-mono/400.css cannot be resolved from src/ui/index.css.

Fixes Termix-SSH/Support#861