## Why
Register the released v0.1.0 rancher secrets plugin so the engine can be mounted. Uses the existing config/plugins discovery + plugin module (added for gpg in #89). Mirrors #90 (litellm import).
## Changes
- Add `config/plugins/vault-plugin-secrets-rancher.yaml` (`type: secret`, `command: vault-plugin-secrets-rancher`, `sha256` pinned to the released binary `d2b17f45…ec574a`, verified against both the vault and openbao v0.1.0 RPMs).
## Merge order
Part 2 of 4. Requires the binary on disk (puppet-prod install) and the deployer policy (#91). Merge before the backend PR.
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Co-authored-by: Ben Vincent <neotheo@gmail.com>
Reviewed-on: #92
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>
