[eshanized]

Summary

• Redesign the sign-in screen with a responsive two-panel layout, clearer brand hierarchy, privacy messaging, and a mailbox preview.
• Polish the login form with upgraded fields, loading state, accessible password visibility control, and a clearer setup path.
• Refresh the shared mailbox shell, message list, sidebar, selected-message workspace, settings, setup wizard, and secondary mail pages through the existing Tailwind/Vite design system.
• Preserve Laravel, Livewire, backend services, database schema, security behavior, and shared-cPanel deployment. No Next.js or production Node.js runtime is introduced.

Verification

• Changes are isolated on ui/premium-mailbox-refresh.
• Visual/browser and CI checks still need to be run against this branch; I have not claimed a local build or browser test passed.