Preserve hook trust bypass in codex exec threads (#26434)

Addresses #26383 and #26452

## Summary

`codex exec --dangerously-bypass-hook-trust` printed the bypass warning,
but valid untrusted hooks still did not run.

Exec applied the flag to its initial config, then lost it when
app-server reloaded config for the new or resumed thread.

## Fix

Forward `bypass_hook_trust: true` through the existing thread request
config override for both start and resume.

The override is omitted when the flag is not enabled, preserving normal
trust behavior.

## Testing

Added:

- A test confirming start and resume preserve the override.
- An end-to-end exec test confirming a `SessionStart` hook runs and
creates a marker file.

codex-rs/exec/src/lib.rs

@@ -138,6 +138,7 @@ pub use exec_events::TurnStartedEvent;
 pub use exec_events::Usage;
 pub use exec_events::WebSearchItem;
 use serde_json::Value;
+use std::collections::HashMap;
 use std::future::Future;
 use std::io::IsTerminal;
 use std::io::Read;
@@ -1054,7 +1055,7 @@ fn thread_start_params_from_config(config: &Config) -> ThreadStartParams {
         approvals_reviewer: approvals_reviewer_override_from_config(config),
         sandbox: sandbox.flatten(),
         permissions,
-        config: None,
+        config: thread_config_overrides_from_config(config),
         ephemeral: Some(config.ephemeral),
         thread_source: Some(ThreadSource::User),
         ..ThreadStartParams::default()
@@ -1079,11 +1080,17 @@ fn thread_resume_params_from_config(config: &Config, thread_id: String) -> Threa
         approvals_reviewer: approvals_reviewer_override_from_config(config),
         sandbox: sandbox.flatten(),
         permissions,
-        config: None,
+        config: thread_config_overrides_from_config(config),
         ..ThreadResumeParams::default()
     }
 }
 
+fn thread_config_overrides_from_config(config: &Config) -> Option<HashMap<String, Value>> {
+    config
+        .bypass_hook_trust
+        .then(|| HashMap::from([("bypass_hook_trust".to_string(), Value::Bool(true))]))
+}
+
 fn permissions_selection_from_config(config: &Config) -> Option<String> {
     config
         .permissions

codex-rs/exec/src/lib_tests.rs

@@ -593,6 +593,32 @@ async fn thread_start_params_include_user_thread_source() {
     );
 }
 
+#[tokio::test]
+async fn thread_lifecycle_params_preserve_hook_trust_bypass() {
+    let codex_home = tempdir().expect("create temp codex home");
+    let cwd = tempdir().expect("create temp cwd");
+    let config = ConfigBuilder::default()
+        .codex_home(codex_home.path().to_path_buf())
+        .harness_overrides(ConfigOverrides {
+            bypass_hook_trust: Some(true),
+            ..Default::default()
+        })
+        .fallback_cwd(Some(cwd.path().to_path_buf()))
+        .build()
+        .await
+        .expect("build config with hook trust bypass");
+    let expected_config = Some(HashMap::from([(
+        "bypass_hook_trust".to_string(),
+        serde_json::Value::Bool(true),
+    )]));
+
+    let start_params = thread_start_params_from_config(&config);
+    let resume_params = thread_resume_params_from_config(&config, "thread-id".to_string());
+
+    assert_eq!(start_params.config, expected_config);
+    assert_eq!(resume_params.config, expected_config);
+}
+
 #[test]
 fn active_profile_selection_uses_profile_id_only() {
     let selection = permission_profile_id_from_active_profile(ActivePermissionProfile::new(