Remove config lockfile support (#38011)

## What changed

- Remove effective-config lockfile export, replay, and validation from session startup.
- Remove the `debug.config_lockfile` settings and generated schema entries.
- Remove feature-config materialization helpers that were only used to create lockfiles.

GitOrigin-RevId: a8c07c1c06325b3ec3dae9a97c36c2488d37df25

codex-rs/thread-manager-sample/src/main.rs

@@ -260,10 +260,6 @@ fn new_config(model: Option<String>, arg0_paths: Arg0DispatchPaths) -> anyhow::R
         memories: MemoriesConfig::default(),
         sqlite: SqliteConfig::from_sqlite_home(codex_home.clone()),
         log_dir: codex_home.join("log").to_path_buf(),
-        config_lock_export_dir: None,
-        config_lock_allow_codex_version_mismatch: false,
-        config_lock_save_fields_resolved_from_model_catalog: true,
-        config_lock_toml: None,
         codex_home,
         history: History::default(),
         ephemeral: true,