Keep step settings and approval environments consistent (#46556)

## Why

Background processes can outlive their launching turn. Their approval reviews need the originating environment's filesystem restrictions, even when the active turn uses a different environment. Remote restrictions must also be resolved using executor paths rather than the local filesystem.

## What changed

- Capture settings and environment selections together in `StepInputs`. Preserve the captured selection during active model updates while allowing environment startup to finish.
- Carry environment IDs into Guardian network and `execve` requests, and use the owning process's environment with current review settings. Refresh environment readiness for network requests that fall back to the active turn.
- Resolve remote denied paths and globs using the executor's policy context. Decline automatic approval when the request's environment is unavailable or an explicitly denied temporary directory cannot be resolved.

## Testing

Add regression coverage for active model updates retaining their environment while the next turn adopts a new selection, background approvals using their owning environment, newly ready network environments, and remote denied paths and globs, including Windows paths and missing temporary-directory metadata.

GitOrigin-RevId: b620d4b030c597a4f430fe0500864fa5469db3d4

codex-rs/core/src/thread_manager_tests.rs

@@ -1955,10 +1955,16 @@ async fn resume_and_fork_do_not_restore_thread_environments_from_rollout() {
         .await
         .expect("build resumed turn context");
     let resumed_turn = prepared_turn;
-    assert_eq!(resumed_turn.environments.turn_environments().count(), 1);
     assert_eq!(
         resumed_turn
-            .environments
+            .initial_environments
+            .turn_environments()
+            .count(),
+        1
+    );
+    assert_eq!(
+        resumed_turn
+            .initial_environments
             .primary()
             .expect("primary environment")
             .cwd(),
@@ -1966,7 +1972,7 @@ async fn resume_and_fork_do_not_restore_thread_environments_from_rollout() {
     );
     assert_ne!(
         resumed_turn
-            .environments
+            .initial_environments
             .primary()
             .expect("primary environment")
             .cwd(),
@@ -1992,10 +1998,13 @@ async fn resume_and_fork_do_not_restore_thread_environments_from_rollout() {
         .await
         .expect("build forked turn context");
     let forked_turn = prepared_turn;
-    assert_eq!(forked_turn.environments.turn_environments().count(), 1);
+    assert_eq!(
+        forked_turn.initial_environments.turn_environments().count(),
+        1
+    );
     assert_eq!(
         forked_turn
-            .environments
+            .initial_environments
             .primary()
             .expect("primary environment")
             .cwd(),
@@ -2003,7 +2012,7 @@ async fn resume_and_fork_do_not_restore_thread_environments_from_rollout() {
     );
     assert_ne!(
         forked_turn
-            .environments
+            .initial_environments
             .primary()
             .expect("primary environment")
             .cwd(),