feat(tournament): add group match creation and enhance match handling

- Implemented createGroupMatches function to generate matches for existing groups without altering group assignments.
- Updated resetMatches function to support optional class filtering when resetting group matches.
- Enhanced frontend components to filter and display group matches based on selected class, improving user experience.
- Adjusted tournament results display to reflect accurate match statistics, including wins and losses.

.gitignore

@@ -7,4 +7,5 @@ backend/.env
 
 backend/images/*
 backend/backend-debug.log
-backend/*.log
+backend/*.log
+backend/.env.local