refactor(cards): SSR collection detail ladder through the builder

All five branch shapes of GET /collections/:id now build cards via the
cards.go adapters: smart (BookCardsFromMediaItems), system-query (same
— gains format_group/badge it previously dropped), scoped
(BookCardsFromCollectionDashRows with the Excluded filter kept), and
the all-libraries branch whose rows distinguish ID vs MediaItemID
(BookCardsFromCollectionItemRows). LibraryTypeMap hoisted to once per
page; both []BookInfo{} error seeds die with the adapters' non-nil
empties.

internal/router/frontend.go

@@ -709,6 +709,8 @@ func registerFrontendRoutes(cfg *Config) {
 			visibleIDs = nil
 		}
 
+		libTypes := handlers.LibraryTypeMap(c.Request().Context(), cfg.Queries)
+
 		if isSmart {
 			// Smart (dynamic) collection: membership is evaluated live —
 			// visible libraries, live items only, any enabled rule matches.
@@ -720,17 +722,7 @@ func registerFrontendRoutes(cfg *Config) {
 			if evalErr != nil {
 				return renderErrorPage(c, "Error loading books", "books_load_error")
 			}
-			bookCards := make([]handlers.BookInfo, 0, len(matches))
+			books = handlers.BookCardsFromMediaItems(matches, libTypes)
-			for _, item := range matches {
-				itemUUID, _ := uuid.FromBytes(item.ID.Bytes[0:16])
-				bookCards = append(bookCards, handlers.BookInfo{
-					MediaItemID:    itemUUID.String(),
-					Title:          item.Title,
-					Author:         getText(item.Author),
-					CoverImagePath: utils.ResolveMediaURL(item.LibraryID, item.CoverImagePath),
-				})
-			}
-			books = bookCards
 		} else if collection.IsSystemCollection.Bool && collection.QueryType.Valid && collection.QueryType.String != "" && collection.QueryType.String != "filter" {
 			dashboardSvc := services.NewDashboardService(cfg.Queries)
 			sections, secErr := dashboardSvc.GetDashboardSections(c.Request().Context(), userUUID, libRes.LibUUID, 1000, []string{}, []string{})
@@ -740,17 +732,7 @@ func registerFrontendRoutes(cfg *Config) {
 
 			for _, section := range sections {
 				if section.CollectionID.String() == collectionID {
-					bookCards := make([]handlers.BookInfo, len(section.Items))
+					books = handlers.BookCardsFromMediaItems(section.Items, libTypes)
-					for i, item := range section.Items {
-						itemUUID, _ := uuid.FromBytes(item.ID.Bytes[0:16])
-						bookCards[i] = handlers.BookInfo{
-							MediaItemID:    itemUUID.String(),
-							Title:          item.Title,
-							Author:         getText(item.Author),
-							CoverImagePath: utils.ResolveMediaURL(item.LibraryID, item.CoverImagePath),
-						}
-					}
-					books = bookCards
 					break
 				}
 			}
@@ -768,7 +750,7 @@ func registerFrontendRoutes(cfg *Config) {
 						Limit:        pgtype.Int4{Int32: 1000, Valid: true},
 					})
 				if collErr != nil {
-					books = []handlers.BookInfo{}
+					books = handlers.BookCardsFromCollectionDashRows(nil, libTypes)
 				} else {
 					var validItems []database.GetCollectionItemsForDashboardRow
 					for _, item := range collItems {
@@ -776,36 +758,14 @@ func registerFrontendRoutes(cfg *Config) {
 							validItems = append(validItems, item)
 						}
 					}
-
+					books = handlers.BookCardsFromCollectionDashRows(validItems, libTypes)
-					bookCards := make([]handlers.BookInfo, len(validItems))
-					for i, item := range validItems {
-						itemUUID, _ := uuid.FromBytes(item.ID.Bytes[0:16])
-						bookCards[i] = handlers.BookInfo{
-							MediaItemID:    itemUUID.String(),
-							Title:          item.Title,
-							Author:         getText(item.Author),
-							CoverImagePath: utils.ResolveMediaURL(item.LibraryID, item.CoverImagePath),
-						}
-					}
-					books = bookCards
 				}
 			} else {
 				collItems, collErr := cfg.Queries.GetCollectionItems(c.Request().Context(), pgtype.UUID{Bytes: collUUID, Valid: true})
 				if collErr != nil {
-					books = []handlers.BookInfo{}
+					collItems = nil
 				}
-
+				books = handlers.BookCardsFromCollectionItemRows(collItems, libTypes)
-				bookCards := make([]handlers.BookInfo, len(collItems))
-				for i, item := range collItems {
-					itemUUID, _ := uuid.FromBytes(item.MediaItemID.Bytes[0:16])
-					bookCards[i] = handlers.BookInfo{
-						MediaItemID:    itemUUID.String(),
-						Title:          item.Title,
-						Author:         getText(item.Author),
-						CoverImagePath: utils.ResolveMediaURL(item.LibraryID, item.CoverImagePath),
-					}
-				}
-				books = bookCards
 			}
 		}
 		// Build collection data