fix(translator): preserve tool name in functionResponse when tool_call_id is reused

[ZIRAN456]

Problem

In multi-turn Agent conversations with extensive tool interactions, random or client-generated tool_call_ids can occasionally collide across turns (or during multi-step execution).

Commit ea333e5 gracefully introduced _dupN deduplication and queued toolResponses to resolve Google's Duplicate function call ID 400 error. However, when resolving the tool name for functionResponse, line 166 still relied on the global lookup:

let name = tcID2Name[rawId];

Because tcID2Name is built by scanning all messages in body.messages beforehand, a later tool call that reuses the same rawId for a different tool will overwrite tcID2Name[rawId].

As a result:

• Earlier turn's functionCall emits the original tool name (e.g. read_file).
• Earlier turn's functionResponse emits the overwritten tool name from the subsequent turn (e.g. patch_file).
• Google Gemini / Antigravity upstream strictly enforces functionCall.name === functionResponse.name and immediately returns:

  HTTP 400 INVALID_ARGUMENT: functionResponse name does not match functionCall name

Solution

1. Record name: tc.function.name directly in toolCallPairs during the assistant turn ({ rawId, uniqueId, name: tc.function.name }).
2. When constructing functionResponse, prioritize localName before falling back to tcID2Name[rawId].
3. Add a unit test to tests/unit/gemini-duplicate-tool-call.test.js covering cross-turn ID reuse with different tool names.

Testing

• Added test case: preserves correct tool name in functionResponse when identical tool_call_id is reused for different tools.
• Verified translation output: both functionCall and functionResponse accurately retain their respective per-turn tool names (read_file -> read_file, patch_file -> patch_file).