Data Mask MVP

- Masks sensitive text that matches email, phone, payment card, and optional generic number patterns. - Blurs common form fields using configurable CSS selectors. - Supports per-site enable or disable from the popup. - Supports semi-transparent overlay mode and partial redaction mode for text. - Supports include and exclude domain rules from the options page. - Supports an in-page floating toolbar for quick pause, resume, and 5-second reveal. - Supports custom regex masking rules configured from the options page. - Supports an options page for advanced rule control.