build(nix): update nci, refactor flake, seperate wrapping, add source filtering (#3657)

Author: 90-008

.github/workflows/cachix.yml

@@ -23,4 +23,4 @@ jobs:
         authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
 
     - name: Build nix flake
-      run: nix build
+      run: nix build -L