Add Formaty to Online tools - #327

Adds Formaty as the first entry in the Online tools section.

Formaty is a free, local-first, browser-only developer data workspace:

• Format & validate JSON, XML, YAML, TOML and CSV
• Convert between formats (JSON ↔ XML / YAML / TOML / CSV)
• Compare: list compare (common / missing / duplicates, with SQL IN / NOT IN / VALUES exports), CSV key-column compare, and side-by-side document diff
• Query with JSONPath and JMESPath (tree / graph / table views)
• Generate SQL (PostgreSQL / MySQL / SQLite), TypeScript types, and JSON Schema from data
• Also includes 40+ single-purpose tool pages and 18+ dev utils

Everything runs client-side in Web Workers — no accounts, no uploads, works offline after the first visit. Source: https://github.com/kdkumawat/formaty (MIT).

The entry follows the section's existing * [Name](url) - Description. style. Happy to adjust the wording or move it further down the list if you prefer.