Add client-side calendar event notification system that evaluates JMAP
CalendarEventAlert triggers and displays toast notifications when alert
times are reached. Includes configurable notification sound, acknowledged
alert persistence, and proactive event fetching for background alerts.
Also mounts ToastContainer globally to fix silent toast failures.
This release significantly expands internationalization support and adds comprehensive identity management features.
Internationalization (i18n):
- Add 5 new languages: Spanish, Italian, German, Dutch, Portuguese
- Expand from 3 to 8 total supported languages
- Redesign language switcher for better scalability (dropdown UI)
- Complete translations for all features across all languages
Identity Management:
- Multiple sender identities with per-identity signatures
- Sub-addressing support (user+tag@domain.com)
- Context-aware tag suggestions for sub-addresses
- Identity badges in email viewer and list
- Full CRUD operations for managing identities
Newsletter Management:
- RFC 2369 List-Unsubscribe support (one-click unsubscribe)
- HTTP and mailto unsubscribe methods
- Security validation prevents XSS attacks
- Two-step confirmation with persistent dismissal
Security & Accessibility:
- Dark mode email readability (intelligent color transformation)
- WCAG 2.0 Level AA color contrast compliance
- Comprehensive XSS prevention with validation utilities
- Unit test coverage for security-critical code (57 validation tests)
Testing:
- Add unit tests for validation utilities
- Add unit tests for email sanitization
- Add unit tests for color transformation
- Full test coverage for XSS attack vectors
