feat: add nixfiles-private and import host user config from there

flake.lock

@@ -18,6 +18,27 @@
         "type": "github"
       }
     },
+    "nixfiles-private": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1745002185,
+        "narHash": "sha256-bdWS7dY1yUe+RfW9a3ySrorYq1S+pWJm4AE2J0yp3+I=",
+        "ref": "refs/tags/0.0.1",
+        "rev": "a0e92bad8feeb269f985a2d8112723bf5926528c",
+        "revCount": 2,
+        "type": "git",
+        "url": "ssh://forgejo@git.werkraum-karlsruhe.org/WRK/nixfiles-private"
+      },
+      "original": {
+        "ref": "refs/tags/0.0.1",
+        "type": "git",
+        "url": "ssh://forgejo@git.werkraum-karlsruhe.org/WRK/nixfiles-private"
+      }
+    },
     "nixos-hardware": {
       "locked": {
         "lastModified": 1743420942,
@@ -68,6 +89,7 @@
     "root": {
       "inputs": {
         "flake-parts": "flake-parts",
+        "nixfiles-private": "nixfiles-private",
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs"
       }