Deploys the Rancher token secrets engine into the cluster, mirroring the litellm
and gpg wiring. The plugin is registered separately (config/plugins) and the
deployer policy is granted separately; this mounts and configures the engine.
- Add rancher_secret_backend module (mount + config via the ranchervaultsecret
provider): rancher_url https://rancher.k8s.syd1.au.unkin.net.
- Add rancher_secret_backend_service_account module: seeds an auto-rotated token
(90d TTL / 45d rotation), reading the seed token from KV at
secret_backend/rancher/service_account/<name> (keys: token, token_name).
- Add rancher_secret_backend_role module + a 'ci' role (1h/8h scoped creds).
- Wire config.hcl discovery, module variables, main.tf module blocks, the
terragrunt inputs, and the rancher provider in root.hcl.
Prereq: populate kv/service/vault/au/syd1/secret_backend/rancher/service_account/admin
with a live Rancher admin token before apply.
Ben Vincent