What's Next? 0.16.0

GLOBAL NAVIGATION LAYOUT

- Removed the old top TASKS / LOOT TRACKER buttons.
- Added a persistent left navigation panel visible on every page.
- Navigation entries:
  TASKS
  LOOT TRACKER
  ABOUT
  SETTINGS
- Added a common page host on the right side of the navigation.
- Tasks retain their existing task input, task list and calendar layout.
- Loot Tracker now renders inside the common page host and no longer covers navigation.
- Added initial About page with addon description and current feature list.
- Added initial Settings page container for upcoming language/interface options.
- Active navigation entry is highlighted.
- Main window widened to 1380 px so the Loot Tracker working area keeps approximately its previous width.
- English DB Builder location and slash command were not changed.
