Migrate Metacontroller webhook from HTTP to HTTPS

[dcruver]

Summary

The Metacontroller sync webhook currently communicates over plain HTTP (http://integrationroute-webhook.keip/webhook/sync). Sync requests contain CR specs which may include secret references, so this traffic should be encrypted.

Context

Identified during PR #44 review. See operator/controller/composite-controller.yaml.

Requirements

• Generate or provision a TLS certificate for the webhook service
• Update the webhook deployment to serve HTTPS (likely via Uvicorn's --ssl-certfile/--ssl-keyfile options or a sidecar)
• Update the CompositeController hook URL to https://
• Consider using the existing cert-manager addon (operator/controller/addons/certmanager/) for certificate provisioning