Update documentation with new features

CHANGELOG.md

@@ -4,6 +4,32 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### 🌙 Mobile Application
+
+- Default to dark theme across the mobile app
+- Filter native calendar events by location to exclude empty ones
+- Async station selection with error handling and alerts
+- Improved notification settings UI
+
+### 📅 Calendar Integration
+
+- **Google Calendar sync** via full OAuth 2.0 flow (token exchange, refresh, and status checks)
+- UI for connecting, syncing, and disconnecting Google accounts in the Calendar panel
+- Batch edit panel for managing event destinations on the web calendar
+- Edit support in AddEventModal for modifying existing events
+
+### 🚉 Public Transport
+
+- HAFAS LocMatch method in API client for finding nearest station to current location
+- Improved station selection with async search and error handling
+- WienerLinien departures hook improvements
+
+### 🔧 API Client
+
+- Added `fetchGoogleCalendarEvents` method for Google Calendar sync
+- Added `findNearestStation` method for geolocation-based station lookup
+- Enhanced HAFAS request handling
+
 ---
 
 ## [1.0.0] — 2025-01-27