fix: force UI difficulty mapping exactly at entrypoint

server/app.py

@@ -688,7 +688,15 @@ def init_env(difficulty: str, compare: bool, agent_mode: str = "Dueling DDQN (Lo
     state.difficulty = difficulty
     state.compare_mode = compare
     state.agent_mode = agent_mode
-    task = get_task(difficulty)
+    
+    # Force map UI conceptual names directly to task IDs
+    val = difficulty.lower().strip()
+    if val == "easy": task_key = "task_1"
+    elif val == "medium": task_key = "task_11"
+    elif val == "hard": task_key = "task_21"
+    else: task_key = val
+    
+    task = get_task(task_key)
     
     # Initialize RL Env
     state.env_rl = task.build_env()