Align rollout trace replay with the same-binary contract (#61199)

## Why

Raw trace events and payloads are implementation details of the recording executable. Matching release or schema versions do not establish compatibility with another binary.

## What changed

- Document that bundles must be reduced by the exact executable that recorded them, with `state.json` as the consumer API and `manifest.json` for discovery and identity.
- Require explicit thread IDs on code-cell runtime events and use structured agent-message metadata instead of parsing legacy assistant-message JSON.
- Include expected schema versions and guidance to use the recording executable in schema mismatch errors.
- Update agent-delivery test fixtures to use structured `agent_message` inputs and check manifest schema rejection directly.

GitOrigin-RevId: 67206fa554f1ba9c1bf9bfdad54840b5d86c5a77

codex-rs/rollout-trace/src/reducer/code_cell.rs

@@ -560,35 +560,6 @@ impl TraceReducer {
         self.add_code_cell_output_item(&code_cell_id, item_id)
     }
 
-    /// Resolves the owning thread for a code-cell runtime event.
-    ///
-    /// Runtime events should carry a thread id, but older/raw paths may only have
-    /// the turn id. The fallback keeps replay strict while avoiding duplicate logic
-    /// in every code-cell event arm.
-    pub(super) fn code_cell_event_thread_id(
-        &self,
-        thread_id: Option<String>,
-        codex_turn_id: Option<&str>,
-        runtime_cell_id: &str,
-        event_name: &str,
-    ) -> Result<String> {
-        if let Some(thread_id) = thread_id {
-            return Ok(thread_id);
-        }
-        let Some(codex_turn_id) = codex_turn_id else {
-            bail!("{event_name} {runtime_cell_id} did not include a thread id");
-        };
-        self.rollout
-            .codex_turns
-            .get(codex_turn_id)
-            .map(|turn| turn.thread_id.clone())
-            .with_context(|| {
-                format!(
-                    "{event_name} {runtime_cell_id} referenced unknown Codex turn {codex_turn_id}"
-                )
-            })
-    }
-
     /// Derives the stable reduced code-cell id from the model-visible exec call id.
     pub(super) fn reduced_code_cell_id_for_model_visible_call(
         model_visible_call_id: &str,