Add: 雛形を追加 #1

	# ========================================
	# DevContainerベースイメージビルドワークフロー
	# ========================================
	name: Build and Push DevContainer Base Image

	on:
	push:
	branches:
	- master
	paths:
	- 'Dockerfile'
	- '.github/workflows/build-image.yml'
	workflow_dispatch:

	env:
	REGISTRY: ghcr.io
	IMAGE_NAME: ${{ github.repository }}

	permissions:
	contents: read
	packages: write

	jobs:
	build-and-push:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout repository
	uses: actions/checkout@v4

	- name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v3

	- name: Log in to Container Registry
	uses: docker/login-action@v3
	with:
	registry: ${{ env.REGISTRY }}
	username: ${{ github.actor }}
	password: ${{ secrets.GITHUB_TOKEN }}

	- name: Extract metadata
	id: meta
	uses: docker/metadata-action@v5
	with:
	images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
	tags: \|
	type=raw,value=latest,enable={{is_default_branch}}
	type=sha,prefix={{branch}}-
	type=ref,event=branch

	- name: Build and push 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
	platforms: linux/amd64,linux/arm64

	- name: Image digest
	run: echo "Image pushed with digest ${{ steps.meta.outputs.digest }}"

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