Dotfiles de la sesión e install.sh para Void

- home/: xinitrc, bashrc, bash_profile, gitconfig, picom, dunst,
  mimeapps.list y el fondo de pantalla. Se enlazan en ~ con la misma ruta.
- xinitrc: feh directamente en vez de .fehbg, y XDG_RUNTIME_DIR a mano solo
  si elogind no lo ha creado.
- mimeapps.list: firefox.desktop en vez del .desktop autogenerado.
- install.sh: instala los paquetes de Void, compila los programas, enlaza
  home/, prepara GnuPG (permisos, pinentry-gtk y agente SSH), copia
  sistema/ y activa servicios y grupos.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016UdJsHrbkmzhoCb6TthP2m

home/.config/mimeapps.list

@@ -0,0 +1,23 @@
+[Default Applications]
+x-scheme-handler/http=firefox.desktop
+x-scheme-handler/https=firefox.desktop
+x-scheme-handler/chrome=firefox.desktop
+text/html=firefox.desktop
+application/x-extension-htm=firefox.desktop
+application/x-extension-html=firefox.desktop
+application/x-extension-shtml=firefox.desktop
+application/xhtml+xml=firefox.desktop
+application/x-extension-xhtml=firefox.desktop
+application/x-extension-xht=firefox.desktop
+
+[Added Associations]
+x-scheme-handler/http=firefox.desktop;
+x-scheme-handler/https=firefox.desktop;
+x-scheme-handler/chrome=firefox.desktop;
+text/html=firefox.desktop;
+application/x-extension-htm=firefox.desktop;
+application/x-extension-html=firefox.desktop;
+application/x-extension-shtml=firefox.desktop;
+application/xhtml+xml=firefox.desktop;
+application/x-extension-xhtml=firefox.desktop;
+application/x-extension-xht=firefox.desktop;