add forge to ci

.forgejo/workflows/build.yaml

@@ -7,12 +7,20 @@ on:
 
 jobs:
   build:
-    runs-on: nixos
+    runs-on: ${{ matrix.runner }}
     strategy:
       matrix:
-        # keep-sorted start
-        host: [muede-lpt2, muede-pc2, hetzner-vpn2]
-        # keep-sorted end
+        include:
+          # keep-sorted start block=yes
+          - host: hetzner-vpn2
+            runner: nixos-aarch64
+          - host: hyperforge
+            runner: nixos-aarch64
+          - host: muede-lpt2
+            runner: nixos
+          - host: muede-pc2
+            runner: nixos
+          # keep-sorted end
     steps:
       - uses: https://code.forgejo.org/actions/checkout@v4
       - run: nix build .#nixosConfigurations.${{ matrix.host }}.config.system.build.toplevel