refactor(router): replace temporary variable pointer pattern with new() builtin

Simplify page number and chapter number pointer creation in reader route
registration by using inline new() instead of local variable + address-of.

internal/router/reader.go

@@ -123,14 +123,12 @@ func registerReaderRoutes(cfg *Config) {
 
 			var pageNumber *int
 			if b.PageNumber.Valid {
-				pn := int(b.PageNumber.Int32)
+				pageNumber = new(int(b.PageNumber.Int32))
-				pageNumber = &pn
 			}
 
 			var chapterNumber *int
 			if b.ChapterNumber.Valid {
-				cn := int(b.ChapterNumber.Int32)
+				chapterNumber = new(int(b.ChapterNumber.Int32))
-				chapterNumber = &cn
 			}
 
 			templateBookmarks[i] = templates.Bookmark{