infra(terraform): add EKS cluster, Elasticache Redis, and ECR modules for cloud deployment

feat(worker): add named Celery queues (high/low priority) with task routing by repo size

fix: deduplicate Celery config fields, fix mypy return-type on task result

fix: run Celery task pipeline safely even inside a running event loop

feat: add Redis/Celery async job queue for repository analysis