refactor(sql): use sqlc.narg() pattern for optional library_id in all library-filtered queries

Convert 12 SQL queries to use sqlc.narg('library_id') instead of
direct @library_id parameters. This allows passing a NULL/invalid
pgtype.UUID to mean "no library filter" (i.e., All Libraries),
making the SQL layer correctly handle the optional filter via:
  (sqlc.narg('library_id')::uuid IS NULL
   OR mi.library_id = sqlc.narg('library_id')::uuid)

Also remove the library_id filter from GetSeriesBooks entirely —
a series is a series regardless of library.

Queries affected:
- GetDashboardSections, GetRecentlyAdded, GetInProgress
- GetHighestRated, GetMostRead, GetAbandonedBooks
- GetLeastRead, GetBooksByTag, GetCollectionItemsForDashboard
- SearchMediaItemsUnified, GetSeriesCardsData

Generated code (queries.sql.go, querier.go) regenerated via sqlc.

internal/database/querier.go

@@ -243,7 +243,7 @@ type Querier interface {
 	GetRefreshToken(ctx context.Context, token pgtype.UUID) (GetRefreshTokenRow, error)
 	GetSavedFilterByID(ctx context.Context, arg GetSavedFilterByIDParams) (SavedFilters, error)
 	GetSavedFilters(ctx context.Context, arg GetSavedFiltersParams) ([]SavedFilters, error)
-	GetSeriesBooks(ctx context.Context, arg GetSeriesBooksParams) ([]MediaItems, error)
+	GetSeriesBooks(ctx context.Context, series pgtype.Text) ([]MediaItems, error)
 	GetSeriesCovers(ctx context.Context, arg GetSeriesCoversParams) ([]GetSeriesCoversRow, error)
 	GetStuckSyncQueueItems(ctx context.Context) ([]SyncQueue, error)
 	GetSyncConflict(ctx context.Context, id pgtype.UUID) (SyncConflicts, error)