Compare OAs across companies

Part of oahelper-mcp by Sirjan Singh.

1. Gather (cheap first)

For each company:

1. oahelper_offline(company). Use the saved pack when it exists.
2. If not saved, oahelper_search(company) (one request) gives set dates, counts and question types. That is enough for the comparison table. Only run oahelper_sync if the user wants topic-level detail, and cap it at about 20 requests per company.

Ask before syncing more than 4 companies in one go; it burns the daily cap.

2. Compare

Use sets from the last 12 months; fall back to older ones and flag it.