feat: apply Nord theme to glow markdown renderer

- Add .config/glow/nord.json — full glamour style using Nord palette
  (Polar Night bg, Frost headings, Aurora syntax, Snow Storm text)
- Configure glow.yml to use the Nord style by default
- Track both glow files in .gitignore whitelist

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -37,5 +37,8 @@
 !.config/bat/config
 !.config/bat/themes/
 !.config/bat/themes/Nord.tmTheme
+!.config/glow/
+!.config/glow/glow.yml
+!.config/glow/nord.json
 !LICENSE
 !README.md