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/router/admin_library.go

@@ -3,6 +3,7 @@ package router
 import (
 	"bookhoard/internal/database"
 	"bookhoard/internal/handlers"
+	"bookhoard/internal/utils"
 	"bookhoard/templates"
 	"bytes"
 	"context"
@@ -213,7 +214,7 @@ func renderLibraryList(c *echo.Context, cfg *Config) error {
 		libData[i] = templates.LibraryData{
 			ID:          libUUID.String(),
 			Name:        lib.Name,
-			Description: getText(lib.Description),
+			Description: utils.PgTextString(lib.Description),
 			TypeName:    lib.TypeName,
 			TypeValue:   lib.TypeName,
 			FolderCount: folderCount,
@@ -262,7 +263,7 @@ func renderLibraryPanelWithError(c *echo.Context, cfg *Config, libraryID pgtype.
 	libData := templates.LibraryData{
 		ID:          libraryIDStr,
 		Name:        lib.Name,
-		Description: getText(lib.Description),
+		Description: utils.PgTextString(lib.Description),
 		TypeName:    lib.TypeName,
 		TypeValue:   lib.TypeName,
 	}