Grant agents AppRole read on the Authentik provider token

A one-off terragrunt import in terraform-authentik is needed to reconcile
resources orphaned by the failed jellyfin apply, and the agents role must
read the Authentik provider token to run it. Revertable after the import.

- Add kv/service/terraform/authentik/read policy (read on
  kv/data/service/terraform/authentik) bound to the agents AppRole

policies/kv/service/terraform/authentik/read.yaml

@@ -0,0 +1,14 @@
+# Lets the agents AppRole read the Authentik provider API token so a coding
+# agent can run a one-off `terragrunt import` in terraform-authentik to
+# reconcile resources orphaned by the failed jellyfin apply. Read-only on the
+# single token path; revert once the import is done. Mirrors the
+# gitea/creds/unkin-agent binding pattern.
+---
+rules:
+  - path: "kv/data/service/terraform/authentik"
+    capabilities:
+      - read
+
+auth:
+  approle:
+    - agents