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/session/step_context.rs

@@ -15,6 +15,14 @@ use codex_otel::SessionTelemetry;
 use codex_protocol::items::ModelInvocationContext;
 use codex_protocol::protocol::TurnContextItem;
 
+/// Inputs for the next step, published together so capture cannot mix versions.
+#[derive(Debug)]
+pub(crate) struct StepInputs {
+    pub(crate) settings: Arc<ResolvedStepSettings>,
+    /// Selection is fixed within this version; attachment startup may still finish.
+    pub(crate) environments: TurnEnvironmentSnapshot,
+}
+
 /// Request-scoped state that may change between model sampling requests.
 pub(crate) struct StepContext {
     pub(crate) turn: Arc<TurnContext>,