fix: remove RC4 decrypt from cockpit_chat, use plaintext api_key

wwwroot/api/cockpit_chat.dspy

@@ -143,12 +143,7 @@ async def _build_context(sor, iteration_id, task_id, max_msgs, system_prompt):
 async def _call_llm(model_info, messages, temperature):
     """Call LLM API directly using model config from llm table."""
     api_base = model_info.api_base.rstrip('/')
-    # Try decrypt; DB may have plaintext or RC4-encrypted keys
-    raw_key = model_info.api_key or ''
-    try:
-        api_key = password_decode(raw_key)
-    except Exception:
-        api_key = raw_key
+    api_key = model_info.api_key or ''
     model_id = model_info.model_id
 
     headers = {