[#31]: handle mcp_tool_call turn items from Codex v0.129.0

[delexw]

Summary

Fixes #31

Codex v0.129.0 (PR #20677) introduced mcp_tool_call and mcp_tool_call_output as first-class response_item turn entries. Previously these new payload types fell through the _ => {} fallback in handle_response_item and were silently discarded, so MCP tool calls from v0.129.0+ sessions would vanish from the parsed turn output.

Changes

src-tauri/src/parser/turn.rs

• Added "mcp_tool_call" handler in handle_response_item: reads server + tool fields (falling back to namespace/name for forward compatibility), reconstructs an mcp__<server> namespace, and registers the call via the existing add_function_call path so it is classified as ToolKind::McpTool. Arguments are accepted as either a JSON object or a pre-stringified string.
• Added "mcp_tool_call_output" handler: finalises the pending call via add_function_call_output, supporting both content-array [{"type":"text","text":"..."}] and plain-string output shapes.

No new types, structs, or public API changes — the fix wires the new JSONL item types into the existing ToolCallBuilder infrastructure.

Tests

Four new tests in parser::turn::tests:

Test	Covers
mcp_tool_call_turn_items_classified_as_mcp_tool	Content-array output; verifies kind, mcp_server, mcp_tool, output, status
mcp_tool_call_turn_items_with_string_output	Plain-string output path
mcp_tool_call_turn_items_with_stringified_arguments	Arguments arriving as a JSON string instead of an object
unknown_response_item_types_are_silently_skipped	Future unknown item types do not cause panics or bogus tool calls

Verification

cargo test --lib  →  63 passed, 0 failed
npx vitest run    → 122 passed, 0 failed
cargo clippy      →  0 warnings
npx oxlint        →  0 warnings / errors
npx oxfmt --check →  all files correctly formatted
npx tsc --noEmit  →  no type errors