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/core/src/config/mod.rs

@@ -1320,6 +1320,16 @@ impl Config {
             Ok(Some(s))
         }
     }
+
+    pub fn set_windows_sandbox_globally(&mut self, value: bool) {
+        crate::safety::set_windows_sandbox_enabled(value);
+        if value {
+            self.features.enable(Feature::WindowsSandbox);
+        } else {
+            self.features.disable(Feature::WindowsSandbox);
+        }
+        self.forced_auto_mode_downgraded_on_windows = !value;
+    }
 }
 
 fn default_model() -> String {