Use nix-env for dependencies instead of container

Match runner's NixOS environment.

💘 Generated with Crush

Assisted-by: Claude Opus 4.5 via Crush <crush@charm.land>

.forgejo/workflows/release.yml

@@ -9,13 +9,10 @@ on:
 jobs:
   build:
     runs-on: default
-    container:
-      image: mcr.microsoft.com/dotnet/sdk:9.0
     steps:
       - name: Install dependencies
-        run: |
-          apt-get update
-          apt-get install -y git ssh nodejs
+        run: nix-env -iA nixpkgs.nodejs nixpkgs.dotnet-sdk_9 nixpkgs.openssh nixpkgs.git
+
       - name: Checkout
         uses: actions/checkout@v4