Add vlogs OIDC application and provider

Onboard the VictoriaLogs query UI at https://vlogs.unkin.net behind
oauth2-proxy, gated on akP-vlogs-admin.

- add config/providers_oauth2/vlogs.yaml reading its client_secret from
  kv/kubernetes/namespace/logging/default/vlogs-oauth-credentials
- add permission group akP-vlogs-admin bound to the vlogs application
- nest akP-vlogs-admin under akR-global-admin

config/permissions/akP-vlogs-admin.yaml

@@ -0,0 +1,3 @@
+# Permission group akP-vlogs-admin (name = filename). Grants admin
+# access to vlogs: bound to the vlogs application, gating the VictoriaLogs UI.
+application: vlogs

config/providers_oauth2/vlogs.yaml

@@ -0,0 +1,21 @@
+# OAuth2/OIDC provider + application for vlogs (the VictoriaLogs query UI,
+# served at https://vlogs.unkin.net in the logging namespace). An oauth2-proxy
+# in front of the UI performs the OIDC login; access is gated on the user's
+# hierarchical ak_groups claim (akP-vlogs-admin).
+# client_secret is read from Vault (seeded out of band), never committed.
+name: vlogs
+authorization_flow: default-provider-authorization-implicit-consent
+invalidation_flow: default-provider-invalidation-flow
+client_type: confidential
+client_id: vlogs
+launch_url: https://vlogs.unkin.net/
+client_secret_vault:
+  mount: kv
+  path: kubernetes/namespace/logging/default/vlogs-oauth-credentials
+scope_mappings:
+  - goauthentik.io/providers/oauth2/scope-openid
+  - goauthentik.io/providers/oauth2/scope-email
+  - goauthentik.io/providers/oauth2/scope-profile
+redirect_uris:
+  - matching_mode: strict
+    url: https://vlogs.unkin.net/oauth2/callback

config/roles/akR-global-admin.yaml

@@ -9,6 +9,7 @@ permissions:
   - akP-jellyfin-admin
   - akP-traefik-admin
   - akP-logviewer-admin
+  - akP-vlogs-admin
   - akP-watchstate-admin
   - akP-repospawner-admin
   - akP-vault-admin