feat: create reusable action for setting up Docker environment in workflows

.github/actions/setup-docker-environment/action.yml

@@ -0,0 +1,14 @@
+name: "Setup Docker Environment"
+description: "Common steps for setting up Docker build environment (checkout, QEMU, and Buildx)"
+
+runs:
+  using: "composite"
+  steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4.2.2
+
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v3.4.0
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3.9.0

.github/workflows/feature-pr-build.yml

@@ -0,0 +1,24 @@
+name: Build Docker Image for Pull Request
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Setup Docker Environment
+        uses: ./.github/actions/setup-docker-environment
+
+      - name: Build Docker image
+        uses: docker/build-push-action@v6.13.0
+        with:
+          context: .
+          push: false
+          tags: ${{ github.repository_owner }}/${{ github.event.repository.name }}:${{ github.event.pull_request.number }}
+          platforms: |
+            linux/amd64
+            linux/arm64

.github/workflows/main.yml

@@ -0,0 +1,33 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+
+env:
+  REGISTRY_URL: gitea.kobim.cloud
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Docker Environment
+        uses: ./.github/actions/setup-docker-environment
+        
+      - name: Log in to Docker registry
+        uses: docker/login-action@v3.3.0
+        with:
+          registry: ${{ env.REGISTRY_URL }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+          
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v6.13.0
+        with:
+          context: .
+          push: true
+          tags: ${{ env.REGISTRY_URL }}/${{ github.repository_owner }}/${{ github.event.repository.name }}:latest
+          platforms: |
+            linux/amd64
+            linux/arm64