refactor(be): 코드 구조 개선 (#300) #4

	name: Backend CI

	on:
	push:
	branches: [main, dev]
	paths: ['backend/**']
	pull_request:
	types: [opened, synchronize, reopened, edited]
	branches: [main, dev]
	paths: ['backend/**']

	# 같은 브랜치에서 연속 트리거 시 이전 잡 취소 (중복/불필요 비용 절감)
	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
	cancel-in-progress: true

	# 최소 권한 원칙
	permissions:
	contents: read

	jobs:
	backend-ci:
	runs-on: ubuntu-latest

	steps:
	- name: Checkout
	uses: actions/checkout@v4
	with:
	fetch-depth: 0

	- name: Set up JDK 21
	uses: actions/setup-java@v4
	with:
	distribution: 'temurin'
	java-version: '21'
	cache: 'gradle' # Gradle 의존성 캐시

	# Gradle 캐시/빌드 최적화 (권장)
	- name: Setup Gradle
	uses: gradle/actions/setup-gradle@v4

	- name: Grant execute permission to gradlew
	working-directory: backend
	run: chmod +x ./gradlew

	# .env 주입 (로그에 값 노출 금지: echo만 파일로 리다이렉트)
	- name: Load .env from secrets
	run: \|
	mkdir -p ./backend
	printf "%s" "${{ secrets.DOT_ENV }}" > ./backend/.env

	- name: Build & Test (backend)
	working-directory: backend
	run: \|
	./gradlew clean test build --no-daemon --warning-mode=all

	# 실패 디버깅용 테스트 리포트/로그 업로드 (항상)
	- name: Upload test reports
	if: always()
	uses: actions/upload-artifact@v4
	with:
	name: backend-test-reports
	path: \|
	backend/build/reports/tests/test
	backend/build/test-results/test
	backend/build/reports/jacoco/*/
	if-no-files-found: ignore

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