Implement healthcheck monitoring for WhatsApp proxy container #440

Summary

Set up automated monitoring and alerts for the healthcheck status of the WhatsApp proxy container, based on the logic in proxy/src/healthcheck.sh.

Details

• The healthcheck.sh script performs a Layer 4 healthcheck for the *.whatsapp.net backend via HAProxy stats on localhost:8199.
• The script checks if the health check returned anything other than "Layer4 check passed" for *.whatsapp_net entries and will exit with a non-zero code if failures are detected.
• When the check fails, an error message is printed and the container exits with code -1.

Tasks

• Review and document the current healthcheck script implementation.
• Set up monitoring to detect failed healthchecks, triggering an alert or notification whenever the script exits with failure.
• Optionally, extend healthcheck logic for other backends or protocols if needed.
• Ensure logging captures details from failed checks for diagnostics.

Reference

• Source: proxy/src/healthcheck.sh

Acceptance Criteria

• Monitoring and alerting are enabled for healthcheck failures.
• Failure logs include description output for diagnosis.
• No changes to functional healthcheck logic unless explicitly requested.