feat: add --resume-id <threadId> option to task command

Summary

The task command currently supports --resume-last (boolean) and --resume (boolean alias) to resume the latest thread, but there is no way to resume a specific thread by ID.

This is needed for workflows that manage multiple concurrent threads (e.g., parallel PR reviews) where --resume-last would pick the wrong thread.

Proposed Change

Add a new --resume-id <threadId> value option:

• --resume-id <threadId> — resume the specified thread
• --resume / --resume-last — resume the latest thread (existing behavior, unchanged)

Using --resume-id instead of overloading --resume preserves backward compatibility with the existing boolean --resume flag used by the rescue command routing.

This aligns with the @cursor/agent-plugin-cc companion which already supports --resume-id <threadId>.

Affected Files

• plugins/codex/scripts/codex-companion.mjs
  • handleTask(): add --resume-id as a value option
  • buildTaskRequest(): pass resumeId through
  • executeTaskRun(): use resumeId directly when provided, fall back to resolveLatestTrackedTaskThread() for --resume-last

Start in plugins/codex/scripts/codex-companion.mjs by reading handleTask(), buildTaskRequest(), and executeTaskRun(). Trace how --resume and --resume-last currently select a thread, then add the specified --resume-id value flow without changing existing boolean behavior. Done means a provided thread ID is used directly, while --resume-last still falls back to resolveLatestTrackedTaskThread().