refactor(utils): one PgTextString for the four pgtype.Text unwrappers

handlers textToString, router textToString, router getText, and utils
normText were four copies of the same NULL-to-empty unwrap (99 call
sites). One exported utils.PgTextString replaces them all; the private
normText (comparison normalizer) stays but is now the odd one out.

Harness fix found on the way: setupTestServer built a full wiring
literal for route registration and then RETURNED a second, sparser
literal that never copied AnnotationService — setup.AnnotationService
was always nil on the struct every test receives. Nobody noticed until
cross_library_move_test became the first caller (it previously used
the now-retired plain CreateMediaHighlight query); it now exercises
the real SaveHighlight path through the wired service.

internal/handlers/cards.go

@@ -114,7 +114,7 @@ func BookCardsFromMediaItems(rows []database.MediaItems, libTypes map[string]str
 		cards = append(cards, buildBookCard(cardSource{
 			ID:          uuid.UUID(r.ID.Bytes),
 			Title:       r.Title,
-			Author:      textToString(r.Author),
+			Author:      utils.PgTextString(r.Author),
 			LibraryID:   r.LibraryID,
 			CoverPath:   r.CoverImagePath,
 			FormatGroup: r.FormatGroup,
@@ -134,7 +134,7 @@ func BookCardsFromCollectionDashRows(rows []database.GetCollectionItemsForDashbo
 		cards = append(cards, buildBookCard(cardSource{
 			ID:          uuid.UUID(r.ID.Bytes),
 			Title:       r.Title,
-			Author:      textToString(r.Author),
+			Author:      utils.PgTextString(r.Author),
 			LibraryID:   r.LibraryID,
 			CoverPath:   r.CoverImagePath,
 			FormatGroup: r.FormatGroup,
@@ -154,7 +154,7 @@ func BookCardsFromCollectionItemRows(rows []database.GetCollectionItemsRow, libT
 		cards = append(cards, buildBookCard(cardSource{
 			ID:          uuid.UUID(r.MediaItemID.Bytes),
 			Title:       r.Title,
-			Author:      textToString(r.Author),
+			Author:      utils.PgTextString(r.Author),
 			LibraryID:   r.LibraryID,
 			CoverPath:   r.CoverImagePath,
 			FormatGroup: r.FormatGroup,
@@ -173,7 +173,7 @@ func BookCardsFromUnified(rows []database.SearchMediaItemsUnifiedRow) []BookInfo
 		cards = append(cards, buildBookCard(cardSource{
 			ID:          uuid.UUID(r.ID.Bytes),
 			Title:       r.Title,
-			Author:      textToString(r.Author),
+			Author:      utils.PgTextString(r.Author),
 			LibraryID:   r.LibraryID,
 			CoverPath:   r.CoverImagePath,
 			FormatGroup: r.FormatGroup,