CI/CD Pipeline for ECS Fargate using AWS CodePipeline and Bitbucket

Act as an AWS CI/CD Specialist. Architect a completely serverless, native continuous delivery pipeline utilizing AWS CodePipeline strictly triggered by commits to the [BRANCH_NAME] branch of the [BITBUCKET_REPO] repository via a Bitbucket StarStar connection. The pipeline topography must mandate an AWS CodeBuild stage executing a highly optimized `buildspec.yml` to compile and push Docker artifacts, followed immediately by an AWS CodeDeploy stage orchestrating the rolling update of an ECS Fargate service. Provide the AWS CDK (TypeScript) or CloudFormation code required to physically provision this entire pipeline pipeline. Ensure you explicitly define the restrictive IAM roles for each stage and enforce strict KMS encryption policies on the central [ARTIFACT_BUCKET].