refactor: move personal site to sites/nrd.sh/

Reorganize for monorepo structure:
- Move content/, templates/, static/, site.toml → sites/nrd.sh/
- Frees root for sukr docs site
- Build with: sukr -c sites/nrd.sh/site.toml

sites/nrd.sh/content/projects/digga.md

@@ -0,0 +1,6 @@
+---
+title: digga
+description: "A Nix flake utility library for managing nixos, hm and devshells"
+weight: 3
+link_to: "https://digga.divnix.com/"
+---