feat: image variants settings screens

docs/design/routes.md

@@ -27,6 +27,8 @@ A global `router.beforeEach` guard reads `meta.auth`. On the first navigation it
 | `/invite/accept` | AuthShell | public | AcceptInvitePage | GET /v1/auth/invite?c=* · POST /v1/auth/invite/accept* |
 | `/:pathMatch(.*)*` | either | any | NotFoundPage | none |
 
+The sidebar reaches `/settings/media/variants` and `/settings/media/cache` through the Media group under Settings (owner and admin only). See [image-variants](screens/image-variants.md), frame 1l.
+
 `/media` and `/article/:id/edit` also gain image variants: GET /v1/media/{id}/variants · POST|DELETE /v1/media/{id}/variants/{name} and the `variants` and `sort=total_size` query parameters on GET /v1/media/ (proposed). See [image-variants](screens/image-variants.md).
 
 Auth values: `public` needs no session, `session` needs a logged-in account (verified or not), `verified` needs a verified account, `admin` needs an admin or owner account, `any` applies to redirects and the catch-all.