Stop overriding job container, use runner default

Setting container: node:20-bookworm replaced the runner's default
job image wholesale, which is where DOCKER_HOST and the docker CLI
were actually pre-configured. Use the default image so that config
applies.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.forgejo/workflows/build.yml

@@ -7,29 +7,14 @@ on:
 
 jobs:
   build-and-push:
+    # Use the runner's default job image as-is: it's pre-configured with
+    # DOCKER_HOST pointing at the runner's dind sidecar (and privileged
+    # access). Overriding `container:` here loses that configuration.
     runs-on: docker
-    # actions/checkout is a JS action and needs Node, so the job container
-    # has to be a Node image. The runner already provides a privileged
-    # container wired up to its own dind sidecar via DOCKER_HOST, so we
-    # just need the docker CLI itself. Plain `docker` commands (rather
-    # than buildx-based actions) pick up DOCKER_HOST directly.
-    container: node:20-bookworm
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Install Docker CLI
-        run: |
-          apt-get update
-          apt-get install -y --no-install-recommends ca-certificates curl
-          install -m 0755 -d /etc/apt/keyrings
-          curl -fsSL https://download.docker.com/linux/debian/gpg -o /etc/apt/keyrings/docker.asc
-          chmod a+r /etc/apt/keyrings/docker.asc
-          echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/debian $(. /etc/os-release && echo $VERSION_CODENAME) stable" \
-            > /etc/apt/sources.list.d/docker.list
-          apt-get update
-          apt-get install -y --no-install-recommends docker-ce-cli
-
       - name: Log in to Forgejo registry
         run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login git.rosenvold.tech -u "${{ github.actor }}" --password-stdin