Add four new integrations with full widget support:
- Uptime Kuma: dashboard monitors, uptime percentage ring, status counts
- Audiobookshelf: library stats, audiobooks/podcasts counts, listening time
- Paperless-ngx: document stats, inbox ratio ring, correspondents/tags
- Navidrome: artist/album/song counts, now playing with track list
Also adds a unified "Audio Stats" widget that merges Navidrome and
Audiobookshelf into a single configurable widget with backend-specific
option visibility.
Includes Vitest specs for pagination, status mapping, and shared utils.
When adding a widget from the "Choose item to add" modal, the widget
edit modal now opens immediately after placement, allowing the user to
configure options and integrations before the widget renders.
All available integrations for the widget are selected by default.