feat(realm): add rbac support for banners (#20782)

Co-authored-by: Adam Altman <adam@redocly.com>
remoteId: rem_01jwbtfqhbbam07z9j9m0etng6
remoteUpdateId: grupd_01kh1e1hwpb8ncfzt9hdpqt2sj
branchName: main
commitSha: 053051e82f8cea1b5a0a9ff537d93a114febbe16
commitUrl: Redocly/redocly@053051e

Author: RomanHotsiy

docs/realm/config/banner.md

@@ -95,6 +95,14 @@ If you ejected the `navbar` component before version `0.128.0`, [update it](../c
   - `error` - Red background
   Default: `info`
 
+---
+
+- rbac
+- object
+- Map of teams to permission levels that determines who can see the banner.
+  Controls the visibility of the banner based on the user's team membership.
+  If specified, only users belonging to teams with at least `read` access will see the banner.
+  For more information, see [RBAC configuration](./rbac.md).
 {% /table %}
 
 ## Configuration
@@ -126,6 +134,22 @@ banner:
     dismissible: true
     target: '**'
 ```
+
+### Role-based visibility
+
+Control banner visibility based on team membership:
+
+```yaml {% title="redocly.yaml" %}
+banner:
+  - content: "🔒 Please log in to see all content!"
+    color: warning
+    rbac:
+      anonymous: read
+      authenticated: none
+```
+
+In this example, the banner is only visible to unauthenticated visitors (`anonymous` team).
+
 Configure a banner in the front matter of a specific page:
 ```md {% title="example.md" %}
 ---