Add Docker and CI Support (#4461)

* Add Docker, Docker Compose, and GitHub Actions CI support

- Added a production-ready `Dockerfile` based on Ruby 3.3.8-bullseye.
- Added `entrypoint.sh` to handle Rails server PID cleanup.
- Added `.dockerignore` to optimize build context.
- Added `docker-compose.yml` for local orchestration of Rails, PostgreSQL 17, and Elasticsearch 7.4.0.
- Added GitHub Actions workflow in `.github/workflows/docker-build-push.yml` to build and push the image to GHCR on pushes to the `dev` branch.

Co-authored-by: CloCkWeRX <365751+CloCkWeRX@users.noreply.github.com>

* Swap to 3.4.8

* Node 22

* Apply suggestion from @CloCkWeRX

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

.github/workflows/docker-build-push.yml

@@ -0,0 +1,43 @@
+name: Docker Build and Push
+
+on:
+  push:
+    branches:
+      - mainline
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max