Preserve namespaces on custom tool calls (#30302)

## Summary

- Preserve the optional namespace on custom tool calls during response
deserialization and app-server replay.
- Use the namespaced tool identifier for streaming argument handling and
tool dispatch.
- Regenerate app-server protocol schemas.
- Add regression tests covering namespace serialization and routing.

## Testing

- Ran affected protocol and app-server test suites.
- Ran the full core test suite; two load-sensitive timing tests passed
when rerun individually.
- Ran Clippy and formatting checks.
- Verified with a local end-to-end app-server replay that the namespace
is preserved through the complete request/response flow.

Author: nhamidi-oai

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

@@ -80,6 +80,7 @@ async fn forward_events_cancelled_while_send_blocked_shuts_down_delegate() {
                     status: None,
                     call_id: "call-1".to_string(),
                     name: "tool".to_string(),
+                    namespace: None,
                     input: "{}".to_string(),
                     internal_chat_message_metadata_passthrough: None,
                 },

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

@@ -513,6 +513,7 @@ fn for_prompt_strips_images_when_model_does_not_support_images() {
             status: None,
             call_id: "tool-1".to_string(),
             name: "js_repl".to_string(),
+            namespace: None,
             input: "view_image".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -582,6 +583,7 @@ fn for_prompt_strips_images_when_model_does_not_support_images() {
             status: None,
             call_id: "tool-1".to_string(),
             name: "js_repl".to_string(),
+            namespace: None,
             input: "view_image".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -1090,6 +1092,7 @@ fn remove_first_item_handles_custom_tool_pair() {
             status: None,
             call_id: "tool-1".to_string(),
             name: "my_tool".to_string(),
+            namespace: None,
             input: "{}".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -1378,6 +1381,7 @@ fn normalize_adds_missing_output_for_custom_tool_call() {
         status: None,
         call_id: "tool-x".to_string(),
         name: "custom".to_string(),
+        namespace: None,
         input: "{}".to_string(),
         internal_chat_message_metadata_passthrough: None,
     }];
@@ -1393,6 +1397,7 @@ fn normalize_adds_missing_output_for_custom_tool_call() {
                 status: None,
                 call_id: "tool-x".to_string(),
                 name: "custom".to_string(),
+                namespace: None,
                 input: "{}".to_string(),
                 internal_chat_message_metadata_passthrough: None,
             },
@@ -1512,6 +1517,7 @@ fn normalize_mixed_inserts_and_removals() {
             status: None,
             call_id: "t1".to_string(),
             name: "tool".to_string(),
+            namespace: None,
             input: "{}".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },
@@ -1556,6 +1562,7 @@ fn normalize_mixed_inserts_and_removals() {
                 status: None,
                 call_id: "t1".to_string(),
                 name: "tool".to_string(),
+                namespace: None,
                 input: "{}".to_string(),
                 internal_chat_message_metadata_passthrough: None,
             },
@@ -1668,6 +1675,7 @@ fn normalize_adds_missing_output_for_custom_tool_call_panics_in_debug() {
         status: None,
         call_id: "tool-x".to_string(),
         name: "custom".to_string(),
+        namespace: None,
         input: "{}".to_string(),
         internal_chat_message_metadata_passthrough: None,
     }];
@@ -1810,6 +1818,7 @@ fn normalize_mixed_inserts_and_removals_panics_in_debug() {
             status: None,
             call_id: "t1".to_string(),
             name: "tool".to_string(),
+            namespace: None,
             input: "{}".to_string(),
             internal_chat_message_metadata_passthrough: None,
         },

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

@@ -10482,6 +10482,7 @@ async fn fatal_tool_error_stops_turn_and_reports_error() {
         status: None,
         call_id: "call-1".to_string(),
         name: "shell_command".to_string(),
+        namespace: None,
         input: "{}".to_string(),
         internal_chat_message_metadata_passthrough: None,
     };