[#35]: resolve MCP tool calls from tool_id in v0.130.0 sessions

[delexw]

Summary

Fixes #35

Codex v0.130.0 (upstream PR #21454) removed string-keyed MCP tool maps from its internal representation. function_call response_item entries for MCP tools no longer carry a flat namespace string (e.g. mcp__server__); instead they carry a structured tool_id: { server, tool } object.

The previous code read only the namespace field, so MCP tools in sessions recorded with v0.130.0+ were silently classified as ToolKind::Unknown rather than ToolKind::McpTool, resulting in missing tool metadata in traces.

Changes

src-tauri/src/parser/toolcall.rs

• Added mcp_server: Option<String> field to PendingCall for direct server storage (bypasses parse_mcp_namespace — needed because that function splits on __ and would misinterpret multi-segment server names like codex_apps__slack).
• Extended add_function_call signature with mcp_server_direct: Option<String> parameter.
• Updated add_function_call_output: checks pending.mcp_server first; only falls through to namespace-based parsing when it is absent. This keeps full backward compatibility with pre-v0.130.0 sessions.
• Updated all PendingCall fallback constructions to include mcp_server: None.

src-tauri/src/parser/turn.rs

• In the function_call response_item handler: when namespace is absent, extracts tool_id.server and passes it as mcp_server_direct to add_function_call. The tool_id path is only taken when namespace is not present, so older sessions are unaffected.

Tests

Three new tests in parser::turn::tests:

Test	Covers
function_call_with_tool_id_classified_as_mcp_tool	v0.130.0 session: function_call with tool_id correctly resolves to McpTool with server, tool name, output, and status
function_call_with_tool_id_multi_segment_server	Server names containing __ (e.g. codex_apps__slack) are stored verbatim without mangling
function_call_namespace_still_works_without_tool_id	Pre-v0.130.0 namespace field path continues to produce correct mcp_server / mcp_tool values

Verification

cargo test --lib  →  62 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
HTTP API (POST /api/sessions) → returns session JSON correctly