fix nix installation

.gitea/workflows/build-kernel.yaml

@@ -15,13 +15,20 @@ jobs:
 
       - name: Set up Nix
         run: |
-          curl -L https://nixos.org/nix/install | sh
+          sudo apt-get update
-          source ~/.nix-profile/etc/profile.d/nix.sh
+          sudo apt-get install -y \
+            curl \
+            git \
+            xz-utils \
+            ca-certificates
+          curl -L https://nixos.org/nix/install | sh -s -- --daemon
 
       - name: Build custom kernel
         run: |
           export NIX_BUILD_CORES=0
           nix-build '<nixpkgs/nixos>' -A config.system.build.kernel --arg configuration ./custom-kernel.nix
+        env:
+          PATH: /nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/default/sbin:/bin:/sbin:/usr/bin:/usr/sbin
 
       - name: Upload kernel artifacts
         uses: actions/upload-artifact@v4