feat(core): store turn_id on ResponseItem metadata (#28360)

## Description

This PR is a followup to https://github.com/openai/codex/pull/28355 and
starts assigning `internal_chat_message_metadata_passthrough.turn_id` to
durable Responses API items created during a turn.

The goal is that those items keep the `turn_id` that introduced them
when Codex resends stateless HTTP context, reconstructs history for
resume/fork paths, or reuses websocket response state.

## What changed

- Set `internal_chat_message_metadata_passthrough.turn_id` when missing
as response items enter durable history, initial/replacement history,
inter-agent communication history, and local compaction summaries.
- Preserve existing item turn IDs instead of overwriting them during
persistence, resume reconstruction, compaction, forked history, and
websocket incremental reuse.
- Keep `compaction_trigger` fieldless because it is a request control,
not a durable response item.
- Update focused history/request assertions and fixtures for stateless
requests, websocket incrementals, compaction, thread injection, prompt
debug, and related CI coverage.

codex-rs/app-server-protocol/schema/json/ClientRequest.json

@@ -2922,16 +2922,6 @@
         },
         {
           "properties": {
-            "internal_chat_message_metadata_passthrough": {
-              "anyOf": [
-                {
-                  "$ref": "#/definitions/InternalChatMessageMetadataPassthrough"
-                },
-                {
-                  "type": "null"
-                }
-              ]
-            },
             "type": {
               "enum": [
                 "compaction_trigger"

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -15594,16 +15594,6 @@
           },
           {
             "properties": {
-              "internal_chat_message_metadata_passthrough": {
-                "anyOf": [
-                  {
-                    "$ref": "#/definitions/v2/InternalChatMessageMetadataPassthrough"
-                  },
-                  {
-                    "type": "null"
-                  }
-                ]
-              },
               "type": {
                 "enum": [
                   "compaction_trigger"

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -11998,16 +11998,6 @@
         },
         {
           "properties": {
-            "internal_chat_message_metadata_passthrough": {
-              "anyOf": [
-                {
-                  "$ref": "#/definitions/InternalChatMessageMetadataPassthrough"
-                },
-                {
-                  "type": "null"
-                }
-              ]
-            },
             "type": {
               "enum": [
                 "compaction_trigger"

codex-rs/app-server-protocol/schema/json/v2/RawResponseItemCompletedNotification.json

@@ -1003,16 +1003,6 @@
         },
         {
           "properties": {
-            "internal_chat_message_metadata_passthrough": {
-              "anyOf": [
-                {
-                  "$ref": "#/definitions/InternalChatMessageMetadataPassthrough"
-                },
-                {
-                  "type": "null"
-                }
-              ]
-            },
             "type": {
               "enum": [
                 "compaction_trigger"

codex-rs/app-server-protocol/schema/json/v2/ThreadResumeParams.json

@@ -1074,16 +1074,6 @@
         },
         {
           "properties": {
-            "internal_chat_message_metadata_passthrough": {
-              "anyOf": [
-                {
-                  "$ref": "#/definitions/InternalChatMessageMetadataPassthrough"
-                },
-                {
-                  "type": "null"
-                }
-              ]
-            },
             "type": {
               "enum": [
                 "compaction_trigger"

codex-rs/app-server-protocol/schema/typescript/ResponseItem.ts

@@ -20,4 +20,4 @@ id?: string,
 /**
  * Set when using the Responses API.
  */
-call_id: string | null, status: LocalShellStatus, action: LocalShellAction, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "function_call", id?: string, name: string, namespace?: string, arguments: string, call_id: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "tool_search_call", id?: string, call_id: string | null, status?: string, execution: string, arguments: unknown, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "function_call_output", id?: string, call_id: string, output: FunctionCallOutputBody, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "custom_tool_call", id?: string, status?: string, call_id: string, name: string, input: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "custom_tool_call_output", id?: string, call_id: string, name?: string, output: FunctionCallOutputBody, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "tool_search_output", id?: string, call_id: string | null, status: string, execution: string, tools: unknown[], internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "web_search_call", id?: string, status?: string, action?: WebSearchAction, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "image_generation_call", id?: string, status: string, revised_prompt?: string, result: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "compaction", id?: string, encrypted_content: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "compaction_trigger", internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "context_compaction", id?: string, encrypted_content?: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "other" };
+call_id: string | null, status: LocalShellStatus, action: LocalShellAction, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "function_call", id?: string, name: string, namespace?: string, arguments: string, call_id: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "tool_search_call", id?: string, call_id: string | null, status?: string, execution: string, arguments: unknown, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "function_call_output", id?: string, call_id: string, output: FunctionCallOutputBody, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "custom_tool_call", id?: string, status?: string, call_id: string, name: string, input: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "custom_tool_call_output", id?: string, call_id: string, name?: string, output: FunctionCallOutputBody, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "tool_search_output", id?: string, call_id: string | null, status: string, execution: string, tools: unknown[], internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "web_search_call", id?: string, status?: string, action?: WebSearchAction, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "image_generation_call", id?: string, status: string, revised_prompt?: string, result: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "compaction", id?: string, encrypted_content: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "compaction_trigger", } | { "type": "context_compaction", id?: string, encrypted_content?: string, internal_chat_message_metadata_passthrough?: InternalChatMessageMetadataPassthrough, } | { "type": "other" };