Prompt to turn on windows sandbox when auto mode selected. (#6618)

- stop prompting users to install WSL 
- prompt users to turn on Windows sandbox when auto mode requested.

<img width="1660" height="195" alt="Screenshot 2025-11-17 110612"
src="https://github.com/user-attachments/assets/c67fc239-a227-417e-94bb-599a8ed8f11e"
/>
<img width="1684" height="168" alt="Screenshot 2025-11-17 110637"
src="https://github.com/user-attachments/assets/d18c3370-830d-4971-8746-04757ae2f709"
/>
<img width="1655" height="293" alt="Screenshot 2025-11-17 110719"
src="https://github.com/user-attachments/assets/d21f6ce9-c23e-4842-baf6-8938b77c16db"
/>

codex-rs/tui/src/app_event.rs

@@ -91,9 +91,17 @@ pub(crate) enum AppEvent {
         failed_scan: bool,
     },
 
-    /// Show Windows Subsystem for Linux setup instructions for auto mode.
+    /// Prompt to enable the Windows sandbox feature before using Auto mode.
     #[cfg_attr(not(target_os = "windows"), allow(dead_code))]
-    ShowWindowsAutoModeInstructions,
+    OpenWindowsSandboxEnablePrompt {
+        preset: ApprovalPreset,
+    },
+
+    /// Enable the Windows sandbox feature and switch to Auto mode.
+    #[cfg_attr(not(target_os = "windows"), allow(dead_code))]
+    EnableWindowsSandboxForAuto {
+        preset: ApprovalPreset,
+    },
 
     /// Update the current approval policy in the running app and widget.
     UpdateAskForApprovalPolicy(AskForApproval),