Advanced AI Prompt for Kubernetes Init Containers for Dependency Checking

Act as a Microservices Reliability Architect. Generate a Deployment manifest for '[APP_NAME]' that eliminates startup crash-loops by leveraging an `initContainer`. The initialization phase must utilize a lightweight alpine/busybox image to execute a blocking shell script (e.g., using `nc` or `wget`). This script must actively poll the cluster DNS to confirm that the backend database/service '[DEPENDENT_SERVICE]' is fully reachable on TCP port '[PORT]'. Implement a resilient retry loop within the script featuring a '[TIMEOUT]' second backoff interval. Ensure the primary application container physically cannot begin its boot sequence until this init sequence exits with a success code.