feat: move extension scope ids into ExtensionData (#22490)

## Summary
- add a scoped level_id to ExtensionData and expose it through
level_id()
- remove thread_id/turn_id parameters from extension contributor inputs
where the scoped ExtensionData already carries that identity
- move turn-scoped extension data onto TurnContext so token usage and
lifecycle contributors can share the same turn store

## Testing
- cargo check -p codex-extension-api -p codex-core --tests
- cargo test -p codex-extension-api
- cargo test -p codex-guardian
- cargo test -p codex-core --lib
record_token_usage_info_notifies_extension_contributors
- cargo test -p codex-core --lib
submission_loop_channel_close_emits_thread_stop_lifecycle
- cargo test -p codex-core --lib
submission_loop_channel_close_aborts_active_turn_before_thread_stop_lifecycle
- just fix -p codex-extension-api
- just fix -p codex-guardian
- just fix -p codex-core
- just fmt

## Note
- Attempted cargo test -p codex-core; it aborted in
agent::control::tests::spawn_agent_fork_last_n_turns_keeps_only_recent_turns
with the existing stack overflow before the full suite completed.

codex-rs/core/src/codex_thread.rs

@@ -149,7 +149,6 @@ impl CodexThread {
             .thread_lifecycle_contributors()
         {
             contributor.on_thread_resume(codex_extension_api::ThreadResumeInput {
-                thread_id: self.codex.session.conversation_id,
                 session_store: &self.codex.session.services.session_extension_data,
                 thread_store: &self.codex.session.services.thread_extension_data,
             });