feat: implement email verification, password reset workflow, and UI dark mode theme

[podlLev]

Overview

This PR introduces account security features—specifically email verification and password reset workflows—alongside database migrations for token lifecycle management. Additionally, it updates the frontend user experience with a application-wide dark mode toggle and dynamic theme styling.

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Key Changes

• Authentication & Account Lifecycle Security:

  • Token Management: Created the VerificationToken domain entity, JPA repository, and data transfer objects to support secure, time-bound token creation and validation.
  • Core Security Services: Implemented MailService for dispatching transactional emails and VerificationService to manage token issuance, verification logic, and password reset flows.
  • API Endpoints & UI Views: Added web endpoints and frontend views for email verification confirmation and account password reset flows.

• Database Migrations & Configuration:

  • Liquibase Integration: Added Liquibase migration scripts and configuration properties to manage schema changes and lifecycle constraints for the new verification token tables.

• Frontend UI & Dynamic Styling:

  • Dark Mode Theme Engine: Added a global dark mode toggle switch and configured CSS styles across application pages for seamless theme toggling.