Set up GitHub Actions CI/CD for ECR deployment

Create a GitHub Actions workflow that builds Docker images and pushes them to AWS ECR, integrating with the deploy.sh script logic and enabling automatic deployments to App Runner.

Completed

• ✅ Workflow triggers on push to main
• ✅ Build job (lint, type check, build) runs first
• ✅ Deploy job (docker build + ECR push) runs after build passes
• ✅ Extracts commit hash, deploy time, GitHub org/project
• ✅ Tags images as :latest and :YYYY.MM.DD
• ✅ Runs on self-hosted runner with Docker
• ✅ AWS CLI installed and credentials configured securely
• ✅ App Runner auto-deploys on new image push