PWA widgets dashboard, lock screen, screensaver with active category

- Dashboard (/dashboard): configurable widget system with 6 widget types
  (current_tasks, category_time, today_progress, next_task, motivace, calendar_mini)
  stored in localStorage widget_config
- Lock screen (/lockscreen): fullscreen with clock, active group badge,
  up to 4 current tasks, gradient from group color, swipe/tap to unlock
- InactivityMonitor: auto-redirect to lockscreen after configurable timeout
  (only in PWA standalone/fullscreen mode)
- Settings: widget toggle switches, inactivity timeout slider, lockscreen preview
- manifest.json: added display_override ["fullscreen","standalone"] + orientation portrait

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tasks/public/manifest.json

@@ -3,6 +3,8 @@
   "short_name": "Tasks",
   "start_url": "/",
   "display": "standalone",
+  "display_override": ["fullscreen", "standalone"],
+  "orientation": "portrait",
   "background_color": "#0A0A0F",
   "theme_color": "#1D4ED8",
   "icons": [