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/agent/control/spawn.rs

@@ -405,7 +405,7 @@ impl LocalAgentControl {
                     "cannot resume multi-agent v2 child {thread_id} with the current parent settings"
                 ))
             })?;
-            Some((parent, turn.environments.clone()))
+            Some((parent, turn.initial_environments.clone()))
         } else {
             None
         };