[#180]: fix(discover): recognise token_budget_abort and inference_stream_cancelled as turn-terminating events

[delexw]

Problem

Codex v0.142.0 introduced token_budget_abort (fired when the rollout token budget is exhausted) and inference_stream_cancelled (fired when inference is cancelled mid-turn). Codex v0.143.0 (PRs #29918 and #30144) now reliably flushes both events to disk during shutdown — previously they could be lost.

The scan_session_file function in discover.rs classifies a session as completed by recognising turn-terminating events (task_complete, turn_aborted). However, token_budget_abort and inference_stream_cancelled fell through to the catch-all _ => {} arm and were silently ignored. As a result, sessions that terminated via budget exhaustion or cancelled inference were incorrectly shown as is_ongoing = true in the session list until the 60-second mtime fallback elapsed.

Fix

Added a combined match arm in the event_msg branch of scan_session_file:

"token_budget_abort" | "inference_stream_cancelled" => {
    is_ongoing = false;
    end_time = v
        .get("timestamp")
        .and_then(|v| v.as_str())
        .map(|s| s.to_string());
}

This mirrors the existing turn_aborted handler and correctly marks the session as not ongoing, capturing end_time from the event timestamp.

Tests

Two regression tests added to src-tauri/src/parser/discover.rs:

• v0143_token_budget_abort_marks_session_not_ongoing — verifies a session file containing token_budget_abort (no task_complete) is discovered with is_ongoing = false and correct end_time.
• v0143_inference_stream_cancelled_marks_session_not_ongoing — same for inference_stream_cancelled.

All 323 Rust lib tests pass. Clippy -D warnings clean.

Fixes #180