feat: rework to use next and host from single dockerfile

.github/workflows/build.yml

@@ -0,0 +1,67 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+      - master
+    tags:
+      - 'v*'
+  pull_request:
+    branches:
+      - main
+      - master
+  workflow_dispatch:
+
+env:
+  IMAGE_NAME: pi-mta-sign
+
+jobs:
+  build:
+    runs-on: ${{ vars.RUNNER || 'ubuntu-latest' }}
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ vars.REGISTRY || 'ghcr.io' }}
+          username: ${{ vars.REGISTRY_USERNAME || github.actor }}
+          password: ${{ secrets.REGISTRY_PASSWORD || secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ vars.REGISTRY || 'ghcr.io' }}/${{ vars.IMAGE_OWNER || github.repository_owner }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=sha,prefix=
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ./docker/Dockerfile
+          platforms: linux/amd64,linux/arm64
+          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