feat: Adds workflow for NixOS build

.github/workflows/kiosk-iso.yml

@@ -2,32 +2,38 @@ name: Build NixOS Kiosk ISO
 
 on:
   push:
-    branches: [ main, profile-install ]
+    branches: [ profile-install ]
   workflow_dispatch:
 
 jobs:
   flake-check:
     runs-on: ubuntu-latest
-    container:
-      image: nixos/nix:2.33.0
     env:
       NIX_CONFIG: extra-experimental-features = nix-command flakes
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Install Nix
+        run: |
+          curl -L https://nixos.org/nix/install | sh
+          . /home/runner/.nix-profile/etc/profile.d/nix.sh
+          nix --version
       - name: Flake check
         run: nix flake check -L
 
   build-iso:
     runs-on: ubuntu-latest
     needs: [ flake-check ]
-    container:
-      image: nixos/nix:2.33.0
     env:
       NIX_CONFIG: extra-experimental-features = nix-command flakes
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Install Nix
+        run: |
+          curl -L https://nixos.org/nix/install | sh
+          . /home/runner/.nix-profile/etc/profile.d/nix.sh
+          nix --version
       - name: Build ISO
         run: |
           nix --version