Add multi-agent runtime metadata types (#25720)

Stack split from #25708. Original PR intentionally left open. This first
PR adds the multi-agent runtime metadata types and catalog plumbing used
by the rest of the stack.

codex-rs/rollout/src/compression_tests.rs

@@ -473,6 +473,7 @@ fn write_rollout(path: &std::path::Path, thread_id: ThreadId, message: &str) ->
             base_instructions: None,
             dynamic_tools: None,
             memory_mode: None,
+            multi_agent_version: None,
         },
         git: None,
     };

codex-rs/rollout/src/metadata_tests.rs

@@ -49,6 +49,7 @@ async fn extract_metadata_from_rollout_uses_session_meta() {
         base_instructions: None,
         dynamic_tools: None,
         memory_mode: None,
+        multi_agent_version: None,
     };
     let session_meta_line = SessionMetaLine {
         meta: session_meta,
@@ -102,9 +103,11 @@ async fn extract_metadata_from_rollout_returns_latest_memory_mode() {
         base_instructions: None,
         dynamic_tools: None,
         memory_mode: None,
+        multi_agent_version: None,
     };
     let polluted_meta = SessionMeta {
         memory_mode: Some("polluted".to_string()),
+        multi_agent_version: None,
         ..session_meta.clone()
     };
     let lines = vec![
@@ -363,6 +366,7 @@ fn write_rollout_in_sessions_with_cwd(
         base_instructions: None,
         dynamic_tools: None,
         memory_mode: None,
+        multi_agent_version: None,
     };
     let session_meta_line = SessionMetaLine {
         meta: session_meta,

codex-rs/rollout/src/recorder.rs

@@ -696,6 +696,7 @@ impl RolloutRecorder {
                         Some(dynamic_tools)
                     },
                     memory_mode: (!config.generate_memories()).then_some("disabled".to_string()),
+                    multi_agent_version: None,
                 };
 
                 (None, Some(log_file_info), path, Some(session_meta))

codex-rs/rollout/src/recorder_tests.rs

@@ -99,6 +99,7 @@ async fn state_db_init_backfills_before_returning() -> anyhow::Result<()> {
             base_instructions: None,
             dynamic_tools: None,
             memory_mode: None,
+            multi_agent_version: None,
         },
         git: None,
     };
@@ -1145,6 +1146,7 @@ async fn resume_candidate_matches_cwd_reads_latest_turn_context() -> std::io::Re
             model: "test-model".to_string(),
             personality: None,
             collaboration_mode: None,
+            multi_agent_version: None,
             realtime_active: None,
             effort: None,
             summary: codex_protocol::config_types::ReasoningSummary::Auto,

codex-rs/rollout/src/session_index_tests.rs

@@ -41,6 +41,7 @@ fn write_rollout_with_metadata(path: &Path, thread_id: ThreadId) -> std::io::Res
                 base_instructions: None,
                 dynamic_tools: None,
                 memory_mode: None,
+                multi_agent_version: None,
             },
             git: None,
         }),

codex-rs/rollout/src/state_db_tests.rs

@@ -158,6 +158,7 @@ fn write_rollout_with_user_message(
                     base_instructions: None,
                     dynamic_tools: None,
                     memory_mode: None,
+                    multi_agent_version: None,
                 },
                 git: None,
             }),

codex-rs/rollout/src/tests.rs

@@ -1274,6 +1274,7 @@ async fn test_updated_at_uses_file_mtime() -> Result<()> {
                 base_instructions: None,
                 dynamic_tools: None,
                 memory_mode: None,
+                multi_agent_version: None,
             },
             git: None,
         }),