Add UserSearch.com to username search engines

[codeyfour]

Summary

• restore UserSearch to the Username Search Engines category using its current usersearch.com domain
• place UserSearch.com at the top of the category
• include the current OSINT Framework metadata fields for features, pricing, registration, and OPSEC

The project was previously listed as UserSearch.org before it was lost during the March 2026 bulk cleanup/rebase in #546. The current domain is live and serves the updated UserSearch platform.

Validation

• python -m json.tool public/arf.json
• confirmed UserSearch.com is the first child under Username Search Engines
• confirmed https://usersearch.com/ returns HTTP 200
• confirmed all CI smoke-test assets exist

Disclosure

I am affiliated with UserSearch.com.