feat: build CRM image in Gitea registry

.gitea/workflows/docker-build.yml

@@ -0,0 +1,62 @@
+name: Build & Push Docker Image to Gitea Registry
+
+on:
+  push:
+    branches: [main]
+
+env:
+  REGISTRY: git.mischlabs.de
+  REGISTRY_USER: MrDiderot
+  REGISTRY_IMAGE: git.mischlabs.de/mrdiderot/crm
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Docker CLI
+        shell: sh
+        run: |
+          if ! command -v docker >/dev/null 2>&1; then
+            echo "Docker CLI not found. Installing static binary..."
+            if command -v curl >/dev/null 2>&1; then
+              curl -fsSL https://download.docker.com/linux/static/stable/x86_64/docker-26.1.4.tgz | tar -xz -C /usr/local/bin --strip-components=1 docker/docker
+            elif command -v wget >/dev/null 2>&1; then
+              wget -qO- https://download.docker.com/linux/static/stable/x86_64/docker-26.1.4.tgz | tar -xz -C /usr/local/bin --strip-components=1 docker/docker
+            else
+              echo "Neither curl nor wget found! Attempting package manager install..."
+              if command -v apt-get >/dev/null 2>&1; then
+                apt-get update && apt-get install -y docker.io
+              elif command -v apk >/dev/null 2>&1; then
+                apk add --no-cache docker-cli
+              else
+                echo "Cannot install Docker CLI!"
+                exit 1
+              fi
+            fi
+          else
+            echo "Docker CLI already installed."
+          fi
+          docker --version
+
+      - name: Log in to Gitea Package Registry
+        shell: sh
+        run: |
+          if [ -z "${{ secrets.REGISTRY_TOKEN }}" ]; then
+            echo "Missing REGISTRY_TOKEN secret."
+            echo "Create a Gitea personal access token for MrDiderot with package Read and Write permission."
+            exit 1
+          fi
+          echo "${{ secrets.REGISTRY_TOKEN }}" | docker login "${{ env.REGISTRY }}" -u "${{ env.REGISTRY_USER }}" --password-stdin
+
+      - name: Build and push Docker image
+        shell: sh
+        run: |
+          docker build \
+            -t ${{ env.REGISTRY_IMAGE }}:latest \
+            -t ${{ env.REGISTRY_IMAGE }}:${{ github.sha }} \
+            .
+          docker push ${{ env.REGISTRY_IMAGE }}:latest
+          docker push ${{ env.REGISTRY_IMAGE }}:${{ github.sha }}