Add SQL queries for dashboard functionality and system collections:
Dashboard Preferences Queries:
- GetDashboardPreferences: Fetch user preferences for a library
- UpsertDashboardPreferences: Create or update user dashboard preferences
- UpdateDashboardPreferences: Update existing preferences
Dashboard Collections Queries:
- GetSystemCollectionsForDashboard: Fetch system collections (user_id IS NULL)
- GetUserCollectionsForDashboard: Fetch user collections marked for dashboard
- DeleteUserSystemCollection: Delete user's copy of a system collection
System Collection Smart Queries:
- GetContinueReadingItems: Books with 0 < progress < 1
- GetRecentlyAddedItems: Newly added items to library
- GetRecentlyReadItems: Books with progress >= 1
- GetNotStartedItems: Books with progress = 0 or no record
Collection Management Queries:
- GetCollectionItemsForDashboard: Fetch collection items with excluded flag
- GetLibraryItems: Fetch all items in a library
These queries support the unified collections architecture where system
defaults and user-created sections are both collections with user_id
NULL for system-owned and NOT NULL for user-created.