docs(FR-2909): align RBAC manual with revoke confirmation modal and refresh screenshots

Resolves #7454(FR-2909)

Follow-up to #7446. Reconciles the RBAC management manual (en/ja/ko/th) with what FR-2819 / FR-2825 actually ship.

- Bump required Backend.AI Manager version 25.4.0 -> 26.4.0 in the RBAC note (rbac_management.md + admin_menu.md, all 4 languages)
- Remove the "Role Status Management" subsection that was misplaced under "View Role Details" (its content describes role-list row actions; Active/Inactive is already covered by the Role List status filter)
- Rewrite "Revoke Users from a Role": the UI changed from a lightweight popconfirm to an irreversible typed-confirmation modal (BAIConfirmModalWithInput). Documents the per-language confirmation string (en: Permanently Delete / ko: 영구 삭제 / ja: 完全に削除 / th: ลบถาวร) and adds a :::danger irreversibility note
- Recapture screenshots from the live UI, replacing stale / hand-built images: rbac_role_detail_drawer.png and rbac_role_scope_tab.png (new localized tab labels Scopes/Permissions/Role Assignments), rbac_revoke_popconfirm.png (new typed modal), rbac_permission_modal.png (real Add Permission modal captured via project-2de2b969-member)
- All 4 language variants kept structurally identical

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: ironAiken2

packages/backend.ai-webui-docs/src/en/admin_menu/admin_menu.md

@@ -1416,7 +1416,7 @@ This page is only for showing current information.
 RBAC (Role-Based Access Control) Management allows superadmins to define roles with fine-grained permissions and assign them to users. You can control which actions specific users are allowed to perform on various resources throughout the Backend.AI system.
 
 :::note
-RBAC Management is only available to superadmins and requires Backend.AI Manager version 25.4.0 or later.
+RBAC Management is only available to superadmins and requires Backend.AI Manager version 26.4.0 or later.
 :::
 
 For detailed information about managing roles, permissions, and user assignments, refer to the dedicated [RBAC Management](#rbac-management) page.

packages/backend.ai-webui-docs/src/en/images/rbac_permission_modal.png

@@ -5,7 +5,7 @@
 RBAC (Role-Based Access Control) Management allows superadmins to define roles with fine-grained permissions and assign them to users. With RBAC, you can control which actions specific users are allowed to perform on various resources throughout the Backend.AI system.
 
 :::note
-RBAC Management is only available to superadmins and requires Backend.AI Manager version 25.4.0 or later.
+RBAC Management is only available to superadmins and requires Backend.AI Manager version 26.4.0 or later.
 :::
 
 To access the RBAC Management page, click **RBAC Management** in the **Admin Settings** section of the sidebar menu.
@@ -97,19 +97,6 @@ To edit a custom role's name or description:
 The Edit button is only available for Custom roles. System roles cannot have their name or description modified. Scopes cannot be modified after role creation in either case.
 :::
 
-### Role Status Management
-
-Roles have two statuses that you can manage from the role list:
-
-- **Active**: The role is currently in effect. You can **Deactivate** an active role to temporarily suspend it.
-- **Inactive**: The role is suspended. You can **Activate** an inactive role to restore it, or **Purge** it to permanently remove it.
-
-Each role row displays a **Deactivate** action button when viewing **Active** roles, or **Activate** and **Purge Role** action buttons when viewing **Inactive** roles.
-
-:::danger
-Purging a role is irreversible. The role and all its associated data will be permanently removed. You must remove all user assignments and permissions from the role before purging.
-:::
-
 ## View Role Scopes
 
 The **Scopes** tab in the role detail drawer lists the scope entries that were assigned to the role at creation time. Each entry constrains the set of targets that permissions on this role can reference.
@@ -205,9 +192,13 @@ The **Role Assignments** tab in the role detail drawer shows which users are ass
 
 ### Revoke Users from a Role
 
-1. In the **Role Assignments** tab, click the **Revoke User** button next to the user you want to remove
-2. A small confirmation popup appears anchored to the button. Click **OK** to revoke the assignment, or **Cancel** to dismiss.
+1. In the **Role Assignments** tab, click the revoke (trash) icon button next to the user you want to remove
+2. A **Revoke User** confirmation modal opens. Type **`Permanently Delete`** into the input field exactly as shown — the **Revoke User** button stays disabled until the entered text matches. Click **Revoke User** to confirm, or **Cancel** to dismiss.
 
 ![](../images/rbac_revoke_popconfirm.png)
 
-Revoking a user removes only that user's assignment to this role; the role itself and its other assignments are kept, and the user can be added back from **Add User** at any time. Because the action is reversible, it uses a lightweight popup confirmation rather than a typed-name confirmation modal.
+Revoking a user removes only that user's assignment to this role; the role itself and its other assignments remain unchanged.
+
+:::danger
+Revoking a user from a role cannot be undone. The confirmation modal requires you to type `Permanently Delete` before the **Revoke User** button is enabled.
+:::

packages/backend.ai-webui-docs/src/en/images/rbac_revoke_popconfirm.png

@@ -1332,7 +1332,7 @@ Backend.AIの各コンポーネントに互換性があるかどうかを確認
 RBAC（ロールベースアクセス制御）管理では、スーパー管理者がきめ細かい権限を持つロールを定義し、ユーザーに割り当てることができます。Backend.AIシステム全体で特定のユーザーがさまざまなリソースに対して実行できる操作を制御できます。
 
 :::note
-RBAC管理はスーパー管理者のみが利用でき、Backend.AI Managerバージョン25.4.0以降が必要です。
+RBAC管理はスーパー管理者のみが利用でき、Backend.AI Managerバージョン26.4.0以降が必要です。
 :::
 
 ロール、権限、ユーザー割り当ての管理の詳細については、[RBAC管理](#rbac-management)ページを参照してください。