fix: remove duplicate tool_call emission from Responses API providers

[daniel-lxs]

Summary

Fixed duplicate tool rendering in the OpenAI Responses API providers (openai-native.ts and openai-codex.ts).

Problem

Tools were being rendered twice because both providers were emitting tool calls through two separate code paths:

1. Streaming path: tool_call_partial events during response.tool_call_arguments.delta → processed by NativeToolCallParser → finalizeRawChunks() at stream end emits tool_call_end → finalizeStreamingToolCall() creates the final ToolUse
2. Done event path: response.output_item.done with function_call/tool_call item → emitted a complete tool_call event → processed separately by Task.ts

Both paths resulted in the same tool being rendered, causing duplication.

Solution

Removed the tool_call emission from the response.output_item.done handler in both providers. The streaming path already handles tool call completion correctly through NativeToolCallParser.

Testing

• All 79 related tests pass (65 openai-native + 7 openai-codex + 7 NativeToolCallParser)

Affected Providers

• openai-native.ts - ✅ Fixed
• openai-codex.ts - ✅ Fixed
• openai.ts (Chat Completions API) - Not affected (uses different event pattern)

[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The fix correctly removes the duplicate tool_call emission from the response.output_item.done handler in both OpenAI Responses API providers. The streaming path through NativeToolCallParser is the proper mechanism for handling tool calls, and this change eliminates the redundant second code path that was causing tools to be rendered twice.

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[hannesrudolph]

LGTM. The removed code was defensive 'backward compatibility' for a non-streaming tool path that doesn't actually exist - createMessage() always streams, and completePrompt() doesn't use tools. The streaming path via NativeToolCallParser properly handles tool completion.

[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The fix correctly removes duplicate tool_call emission from response.output_item.done handlers in both OpenAI Responses API providers. The streaming path through tool_call_partial events and NativeToolCallParser already handles tool call completion properly, making the removed code redundant.

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}