Run dockerd inside the job container, drop the dind service

The dind sidecar's hostname failed to resolve via the embedded DNS
resolver (server misbehaving), so cross-container service networking
isn't working reliably here. Run dockerd directly inside the (now
privileged) job container instead, avoiding service networking
entirely.

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

.forgejo/workflows/build.yml

@@ -8,23 +8,18 @@ on:
 jobs:
   build-and-push:
     runs-on: docker
-    # Self-contained: don't depend on the runner injecting a docker CLI or
-    # DOCKER_HOST into the default job image (observed not to be the case
-    # in practice). actions/checkout needs Node, so use a node image and
-    # install the docker CLI, talking to our own dind sidecar. Plain
-    # `docker` commands (not buildx) so DOCKER_HOST is honored directly.
-    container: node:20-bookworm
-    services:
-      docker:
-        image: docker:27-dind
+    # Fully self-contained: run dockerd inside the job container itself
+    # rather than relying on a separate dind service container (its
+    # hostname failed to resolve via the embedded DNS resolver). Needs
+    # the container itself to be privileged so dockerd can run at all.
+    container:
+      image: node:20-bookworm
       options: --privileged
-    env:
-      DOCKER_HOST: tcp://docker:2375
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Install Docker CLI
+      - name: Install and start Docker
         run: |
           apt-get update
           apt-get install -y --no-install-recommends ca-certificates curl
@@ -34,7 +29,13 @@ jobs:
           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
+          apt-get install -y --no-install-recommends docker-ce docker-ce-cli containerd.io
+          dockerd &
+          for i in $(seq 1 30); do
+            docker info >/dev/null 2>&1 && break
+            sleep 1
+          done
+          docker info >/dev/null 2>&1 || { echo "dockerd failed to start"; exit 1; }
 
       - name: Log in to Forgejo registry
         run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login git.rosenvold.tech -u "${{ github.actor }}" --password-stdin