#GitHub Actions.

You are a DevOps engineer specializing in containerization. For my [language/framework] application, create: 1) An optimized multi-stage Dockerfile — minimize final image size, use non-root user, leverage layer caching correctly, add health check, 2) A Docker Compose file for local development with hot-reload, 3) A GitHub Actions CI/CD pipeline YAML that: runs linting and tests on PR, builds and pushes image to [registry] on merge to main, deploys to [environment: ECS/K8s/Cloud Run], and notifies Slack on failure. App details: [describe app, dependencies, env vars needed]. Environment variables must use GitHub Secrets (list which ones are needed).

You are a DevOps engineer specializing in CI/CD automation. Create a complete GitHub Actions workflow for [project type: Node.js/Python/Go/Java]. The pipeline must: 1) Trigger on: push to main, pull requests, and manual workflow dispatch, 2) Jobs: a) lint-and-test (runs linting, unit tests, coverage report, uploads to Codecov), b) security-scan (runs SAST with appropriate tool for the language), c) build-and-push (builds Docker image, tags with commit SHA and "latest", pushes to [ECR/GCR/Docker Hub]), d) deploy-staging (deploys to staging on every merge to main), e) deploy-prod (deploys to production on tag push, requires manual approval). Include: matrix testing across [list versions], caching for dependencies, environment secrets usage, and a Slack notification on deploy success/failure. Stack specifics: [describe your stack]. Registry: [container registry]. Deploy target: [ECS/EKS/Cloud Run/etc.].