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/edit.rs

@@ -550,6 +550,15 @@ impl ConfigEditsBuilder {
         self
     }
 
+    /// Enable or disable a feature flag by key under the `[features]` table.
+    pub fn set_feature_enabled(mut self, key: &str, enabled: bool) -> Self {
+        self.edits.push(ConfigEdit::SetPath {
+            segments: vec!["features".to_string(), key.to_string()],
+            value: value(enabled),
+        });
+        self
+    }
+
     /// Apply edits on a blocking thread.
     pub fn apply_blocking(self) -> anyhow::Result<()> {
         apply_blocking(&self.codex_home, self.profile.as_deref(), &self.edits)