feat: make manual-images list dynamic and resolve checkmark encoding issues

backend/compile_json.py

@@ -23,7 +23,7 @@ def main():
 
     for mf in sorted(manual_files):
         try:
-            with open(mf, "r") as f:
+            with open(mf, "r", encoding="utf-8") as f:
                 data = json.load(f)
                 manual_list.append(data)
         except Exception as e: