Introduces user isolation mode, allowing domains, groups, and tags to be visible only to their owners when enabled. Adds user_id fields to domains and notification_groups, updates models and controllers for isolation-aware queries, and provides admin UI and endpoints for transferring domains and groups between users (single and bulk). Includes migration, settings UI, and routes for toggling isolation mode and handling data migration.
Introduces CSRF protection to all sensitive controller actions, integrates configurable CAPTCHA (reCAPTCHA v2/v3, Turnstile) for authentication and registration flows, and centralizes input validation via a new InputValidator helper. Adds new helpers and services for CSRF and CAPTCHA, updates settings and migration for CAPTCHA configuration, and enhances logging and error handling in TLD registry import processes. Also improves validation for user, domain, group, and profile inputs throughout the application.
