Adds back scripts/start_validator.sh and render.yaml so the operator's
Render service has something to run. Both are tagged OPERATOR-ONLY in
their banners — public miners do not need them.

Adapted to the new on-chain CLI: --port and --burn are gone, service
type is now "worker" (no port binding) since the validator is a one-shot
per-epoch process. Reads ARCHIVE_TIER_2_URLS as a comma-separated env var.

These files will move to a private deploy repo soon. Tracking:
github.com/jayesh727/tao-discovery-deploy.