refactor(templates): add error toast support to page templates

Update all page templates to accept an optional error message parameter
and display it via the ErrorToast component when data loading fails.

templates/progress.templ

@@ -2,7 +2,7 @@ package templates
 
 import "bookhoard/internal/handlers"
 
-templ Progress(user User, progressData []handlers.ProgressWithMedia) {
+templ Progress(user User, progressData []handlers.ProgressWithMedia, errorMessage string) {
     <!DOCTYPE html>
     <html lang="en">
     <head>
@@ -108,6 +108,8 @@ templ Progress(user User, progressData []handlers.ProgressWithMedia) {
                 window.location.href = '/login';
             }
         </script>
+
+        @ErrorToast(errorMessage)
     </body>
     </html>
 }