Configure workflows for cidev branch isolation

- test-nixos.yaml: Only runs on cidev branch, adds nix test command before upterm
- ci.yaml: Excludes cidev branch to prevent normal CI from running there

The cidev branch is used for isolated NixOS test development without affecting
the main CI pipeline.

Author: Lillecarl

.github/workflows/ci.yaml

@@ -5,6 +5,7 @@ on:
   push:
     branches:
       - '*'
+      - '!cidev'
     tags:
       - 'v*'
   workflow_dispatch:

.github/workflows/test-nixos.yaml

@@ -3,8 +3,7 @@
 on:
   push:
     branches:
-      - '*'
-  pull_request:
+      - cidev
   workflow_dispatch:
 
 env:
@@ -38,5 +37,8 @@ jobs:
           echo "${{ secrets.NIXBUILD_KEY }}" | install -D -m 600 /dev/stdin ~/.ssh/nixbuild_key
           install -m 644 "${{ github.workspace }}/.github/assets/ssh-config" ~/.ssh/config
 
+      - name: Run nixos test
+        run: nix run --file . nixosTests.containerd.driverInteractive -- --no-interactive
+
       - name: Setup upterm session
         uses: owenthereal/action-upterm@v1