Feature request: Add integration with Simple Basic Contact Form plugin

[arnelap]

as requested https://wordpress.org/support/topic/simple-basic-contact-form-integration/

[faisalahammad]

I've submitted PR #820 to add this integration.

The implementation hooks into scf_filter_contact_form (to inject the opt-in checkbox) and scf_send_email (to process subscriptions), following the same pattern as the existing CF7 integration. All existing tests pass.