Make yolo skip managed-network tool enforcement (#18042)

## Summary

This makes `DangerFullAccess` / yolo tool execution fully opt out of
managed-network enforcement.

Previously, yolo turns could have `turn.network` stripped while tool
orchestration still derived `enforce_managed_network=true` from
`requirements.toml.network`. That created an inconsistent state where
the turn had no managed proxy attached, but tool execution still behaved
like managed networking was active.

This updates the tool orchestration and JS REPL paths to treat managed
networking as active only when the current turn actually has
`turn.network`.

## Behavior

- Yolo / `DangerFullAccess`: no managed proxy, no managed-network
enforcement.
- Guardian / workspace-write with managed proxy: managed-network
enforcement still applies.
- Avoids the half-state where yolo has no proxy but still gets
managed-network sandbox behavior.

## Tests

- `just fmt`
- `cargo test -p codex-core
danger_full_access_tool_attempts_do_not_enforce_managed_network --
--nocapture`
- `cargo test -p codex-core danger_full_access -- --nocapture`
- `just fix -p codex-core`

Co-authored-by: jgershen-oai <jgershen@openai.com>

codex-rs/core/src/tools/js_repl/mod.rs

@@ -1033,18 +1033,13 @@ impl JsReplManager {
         }
 
         let sandbox = SandboxManager::new();
-        let has_managed_network_requirements = turn
-            .config
-            .config_layer_stack
-            .requirements_toml()
-            .network
-            .is_some();
+        let managed_network_active = turn.network.is_some();
         let sandbox_type = sandbox.select_initial(
             &turn.file_system_sandbox_policy,
             turn.network_sandbox_policy,
             SandboxablePreference::Auto,
             turn.windows_sandbox_level,
-            has_managed_network_requirements,
+            managed_network_active,
         );
         let command = SandboxCommand {
             program: node_path.into_os_string(),
@@ -1067,7 +1062,7 @@ impl JsReplManager {
                 file_system_policy: &turn.file_system_sandbox_policy,
                 network_policy: turn.network_sandbox_policy,
                 sandbox: sandbox_type,
-                enforce_managed_network: has_managed_network_requirements,
+                enforce_managed_network: managed_network_active,
                 network: None,
                 sandbox_policy_cwd: &turn.cwd,
                 codex_linux_sandbox_exe: turn.codex_linux_sandbox_exe.as_deref(),