feat: Add GitHub Actions for automated Docker image builds

Add comprehensive CI/CD pipeline for building and publishing Docker images
to GitHub Container Registry (ghcr.io).

Components:
- build-and-push.yaml: Main workflow for building and pushing images
  - Triggers on push to main, tags, PRs, and manual dispatch
  - Multi-tag strategy (latest, semver, sha, branch)
  - Docker buildx with layer caching
  - Automatic GHCR authentication
  - Platform: linux/amd64

- release.yaml: Automated GitHub releases on version tags
  - Auto-generates release notes from commits
  - Creates GitHub release with Docker pull command

- dependabot.yml: Automated dependency updates
  - Weekly updates for GitHub Actions
  - Weekly updates for Docker base images

- PULL_REQUEST_TEMPLATE.md: PR template with testing checklist

Updated README:
- Add build status badge
- Update image pull instructions
- Reference automated builds

Image tagging strategy:
- main branch → :latest, :main, :main-{sha}
- v1.2.3 tag → :v1.2.3, :1.2, :1, :latest
- PR → :pr-{number}

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,36 @@
+## Description
+
+<!-- Describe your changes in detail -->
+
+## Type of Change
+
+<!-- Mark with an `x` all that apply -->
+
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] New feature (non-breaking change which adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] Documentation update
+- [ ] CI/CD update
+
+## Testing
+
+<!-- Describe the tests you ran to verify your changes -->
+
+- [ ] Built Docker image locally
+- [ ] Tested container startup
+- [ ] Tested repository cloning
+- [ ] Tested Happy Coder integration
+- [ ] Tested VNC web interface
+
+## Checklist
+
+- [ ] My code follows the style guidelines of this project
+- [ ] I have performed a self-review of my own code
+- [ ] I have commented my code, particularly in hard-to-understand areas
+- [ ] I have made corresponding changes to the documentation
+- [ ] My changes generate no new warnings
+- [ ] I have tested that the Docker image builds successfully
+
+## Screenshots (if applicable)
+
+<!-- Add screenshots to help explain your changes -->

.github/dependabot.yml

@@ -0,0 +1,19 @@
+version: 2
+updates:
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    labels:
+      - "dependencies"
+      - "github-actions"
+
+  # Maintain dependencies for Docker
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    labels:
+      - "dependencies"
+      - "docker"

.github/workflows/build-and-push.yaml

@@ -0,0 +1,64 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - 'v*'
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=sha,prefix={{branch}}-
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          platforms: linux/amd64

.github/workflows/release.yaml

@@ -0,0 +1,51 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+  packages: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Generate Release Notes
+        id: notes
+        run: |
+          # Get the tag message or generate from commits
+          TAG_MESSAGE=$(git tag -l --format='%(contents)' ${{ github.ref_name }})
+          if [ -z "$TAG_MESSAGE" ]; then
+            # Generate from commit messages since last tag
+            PREV_TAG=$(git describe --tags --abbrev=0 ${{ github.ref_name }}^ 2>/dev/null || echo "")
+            if [ -z "$PREV_TAG" ]; then
+              COMMITS=$(git log --pretty=format:"- %s (%h)" ${{ github.ref_name }})
+            else
+              COMMITS=$(git log --pretty=format:"- %s (%h)" ${PREV_TAG}..${{ github.ref_name }})
+            fi
+            NOTES="## Changes\n\n${COMMITS}\n\n## Docker Image\n\n\`\`\`bash\ndocker pull ghcr.io/${{ github.repository }}:${{ github.ref_name }}\n\`\`\`"
+          else
+            NOTES="${TAG_MESSAGE}\n\n## Docker Image\n\n\`\`\`bash\ndocker pull ghcr.io/${{ github.repository }}:${{ github.ref_name }}\n\`\`\`"
+          fi
+          echo "notes<<EOF" >> $GITHUB_OUTPUT
+          echo -e "$NOTES" >> $GITHUB_OUTPUT
+          echo "EOF" >> $GITHUB_OUTPUT
+
+      - name: Create Release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref_name }}
+          release_name: Release ${{ github.ref_name }}
+          body: ${{ steps.notes.outputs.notes }}
+          draft: false
+          prerelease: false

README.md

@@ -1,5 +1,7 @@
 # Antigravity Dev Container
 
+![Build and Push](https://github.com/cpfarhood/devcontainer/actions/workflows/build-and-push.yaml/badge.svg)
+
 A containerized development environment with GUI access, featuring:
 - **Antigravity** (VSCode/Cloud IDE) via web browser
 - **Happy Coder** - AI-powered development assistant
@@ -35,11 +37,22 @@ A containerized development environment with GUI access, featuring:
 
 ## Quick Start
 
-### 1. Build the Image
+### 1. Get the Image
+
+The image is automatically built and published to GitHub Container Registry on every push to main.
 
 ```bash
-docker build -t ghcr.io/cpfarhood/antigravity:latest .
+# Pull the latest image
-docker push ghcr.io/cpfarhood/antigravity:latest
+docker pull ghcr.io/cpfarhood/devcontainer:latest
+
+# Or pull a specific version
+docker pull ghcr.io/cpfarhood/devcontainer:v1.0.0
+```
+
+**Building locally (optional):**
+```bash
+docker build -t ghcr.io/cpfarhood/devcontainer:latest .
+docker push ghcr.io/cpfarhood/devcontainer:latest
 ```
 
 ### 2. Configure Secrets