Add LiteLLM RBAC: akP-litellm groups + role claim mapping

Bring LiteLLM into the two-tier RBAC and map groups to LiteLLM roles.

- akP-litellm-admin / akP-litellm-user permission groups (bound to the litellm
  app for access); added to akR-global-admin / akR-standard-user roles.
- Generic per-provider role_mappings: emit an app role claim computed from
  effective (hierarchical) group membership. LiteLLM: emits `litellm_role`
  (proxy_admin for akP-litellm-admin, internal_user for akP-litellm-user, else
  internal_user_view_only); LiteLLM reads it via GENERIC_USER_ROLE_ATTRIBUTE.

Validated: plan 5 to add, 3 to change; generated role expression renders correctly.

config/permissions/akP-litellm-admin.yaml

@@ -0,0 +1,3 @@
+# Permission group akP-litellm-admin (name = filename). Grants admin
+# access to litellm: bound to the litellm application and mapped to its role.
+application: litellm

config/permissions/akP-litellm-user.yaml

@@ -0,0 +1,3 @@
+# Permission group akP-litellm-user (name = filename). Grants user
+# access to litellm: bound to the litellm application and mapped to its role.
+application: litellm

config/providers_oauth2/litellm.yaml

@@ -16,3 +16,14 @@ scope_mappings:
 redirect_uris:
   - matching_mode: strict
     url: https://litellm.k8s.syd1.au.unkin.net/sso/callback
+# Emit a `litellm_role` claim from group membership (rules in privilege order).
+# LiteLLM requests the `litellm_role` scope and reads it via
+# GENERIC_USER_ROLE_ATTRIBUTE. akP-litellm-admin is inherited by akR-global-admin.
+role_mappings:
+  claim: litellm_role
+  default: internal_user_view_only
+  rules:
+    - group: akP-litellm-admin
+      role: proxy_admin
+    - group: akP-litellm-user
+      role: internal_user

config/roles/akR-global-admin.yaml

@@ -3,3 +3,4 @@ permissions:
   - akP-grafana-admin
   - akP-argocd-admin
   - akP-rancher-admin
+  - akP-litellm-admin

config/roles/akR-standard-user.yaml

@@ -3,3 +3,4 @@ permissions:
   - akP-grafana-user
   - akP-argocd-user
   - akP-rancher-user
+  - akP-litellm-user