Registers Polyglot Translate as a translation-type connector in the WordPress 7.0 Connectors API.
Preflight API key validation via GET /v1/health (warn-don’t-block strategy).
Public helpers for plugin developers: polyglot_get_api_key(), polyglot_get_api_base_url(), polyglot_is_connected(), polyglot_get_connector_id(), polyglot_get_api_key_source().
Site Health check integration (top-level test + debug info section).
Secure credential management via Settings → Connectors (with environment variable + PHP constant overrides for enterprise hosting).
Optional custom API endpoint override via Settings → Polyglot Translate.
Localization-ready: English source, Serbian (sr_RS) translation included.
