Use Docker-in-Docker container for builds

Root cause: act_runner provides minimal environment without sudo
or Docker CLI. Cannot install packages in workflow.

Solution: Use docker:24-dind container which includes Docker CLI
and daemon. Runs with --privileged to allow nested containers.

Changes:
- Use docker:24-dind as job container
- Remove installation steps (Docker pre-installed)
- Keep simple login, build, push workflow

Also added alternative solution file showing how to configure
runner with Docker CLI for better performance.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.gitea/workflows/build-deploy-alternative.yml.disabled

@@ -0,0 +1,80 @@
+# ALTERNATIVE SOLUTION: Configure runner with Docker CLI pre-installed
+#
+# This file shows how to set up the Gitea runner to have Docker CLI available
+# by default, eliminating the need for Docker-in-Docker.
+#
+# SETUP INSTRUCTIONS:
+#
+# 1. SSH into your server where the Gitea runner is running
+#
+# 2. Find the runner container or installation:
+#    docker ps | grep act_runner
+#
+# 3. Option A: If runner is in Docker, create custom runner image
+#    Create a Dockerfile:
+#
+#    FROM gitea/act_runner:latest
+#    RUN apk add --no-cache docker-cli
+#
+#    Build and use:
+#    docker build -t gitea-runner-with-docker .
+#    # Update docker-compose or run command to use this image
+#
+# 4. Option B: If runner is installed on host, install Docker CLI:
+#
+#    # For Ubuntu/Debian host
+#    curl -fsSL https://get.docker.com -o get-docker.sh
+#    sh get-docker.sh
+#
+#    # Restart the runner service
+#    systemctl restart act_runner
+#
+# 5. Once Docker CLI is available in runner, use this simpler workflow:
+
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Verify Docker is available
+        run: docker version
+
+      - name: Log in to Gitea Container Registry
+        run: |
+          echo "${{ secrets.GITHUB_TOKEN }}" | docker login code.puffinoffset.com -u ${{ github.actor }} --password-stdin
+
+      - name: Build Docker image
+        run: |
+          docker build -t code.puffinoffset.com/matt/puffin-app:latest \
+                       -t code.puffinoffset.com/matt/puffin-app:main-${{ github.sha }} \
+                       .
+
+      - name: Push Docker images
+        run: |
+          docker push code.puffinoffset.com/matt/puffin-app:latest
+          docker push code.puffinoffset.com/matt/puffin-app:main-${{ github.sha }}
+
+      - name: Show image info
+        run: |
+          docker images | grep puffin-app
+
+# BENEFITS OF THIS APPROACH:
+# - Faster workflow execution (no container setup overhead)
+# - Simpler workflow file
+# - Better caching between builds
+# - More control over runner environment
+#
+# WHEN TO USE:
+# - If you have access to modify the runner
+# - If you run multiple workflows that need Docker
+# - For production environments where performance matters

.gitea/workflows/build-deploy.yml

@@ -8,25 +8,14 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    container:
+      image: docker:24-dind
+      options: --privileged
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Install Docker CLI
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y ca-certificates curl
-          sudo install -m 0755 -d /etc/apt/keyrings
-          sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
-          sudo 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/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
-          sudo apt-get update
-          sudo apt-get install -y docker-ce-cli
-
-      - name: Verify Docker installation
-        run: docker version
-
       - name: Log in to Gitea Container Registry
         run: |
           echo "${{ secrets.GITHUB_TOKEN }}" | docker login code.puffinoffset.com -u ${{ github.actor }} --password-stdin