fix: remove SK decryption, use plaintext AK/SK directly

reallife_asset/rl_volcengine_client.py

@@ -66,9 +66,8 @@ async def call_volcengine_api(vendor, operation, params, api_mapping):
         if not ak or not sk_encrypted:
             return {"error": "AK/SK未配置"}
         
-        # Decrypt SK
-        env = ServerEnv()
-        sk = env.password_decode(sk_encrypted)
+        # AK/SK are stored in plaintext
+        sk = sk_encrypted
     
     # Build signed request
     now = datetime.datetime.utcnow()