Allow environment selection updates during an active turn (#47435)

## What changed

- Add `environments` to `TurnSettingsUpdate` to replace the selection for subsequent steps without changing future turns.
- Capture model settings and environments together so combined updates apply or reject atomically, while existing steps retain their captured selection.
- Validate environment IDs, working directories, configuration ownership, and permission requirements against the running turn's selections.
- Preserve executor startup behavior when switching environments and use the step's local working directory for tool hooks.

## Testing

Add coverage for workspace switching and restoration on the next turn, atomic model and environment updates, permission validation, executor connection waits, and replacement of pending environment selections.

GitOrigin-RevId: 02b5c57a78fd594b2aed84fc09d9e99eb97be28c

codex-rs/core/src/unified_exec/process_manager.rs

@@ -897,11 +897,7 @@ impl UnifiedExecProcessManager {
         };
         let _interaction_guard = locked_process.interaction_lock().lock_owned().await;
         // A queued write must observe strict review enabled while it was waiting.
-        let strict_auto_review = context
-            .session
-            .active_turn_context_and_strict_auto_review()
-            .await
-            .is_some_and(|(_, _, strict)| strict);
+        let strict_auto_review = context.session.strict_auto_review_enabled().await;
         let approval = {
             let store = self.process_store.lock().await;
             let entry = store