refactor(config): 移除未使用的配置参数

移除topic_state和control_frequency配置项，简化默认配置加载逻辑

src/config.cpp

@@ -13,10 +13,6 @@ void CustomConfig::loadDefaults() {
     // Topic settings
     topic_prefix = TOPIC_PREFIX;
     topic_cmd = TOPIC_CMD;
-    topic_state = TOPIC_STATE;
-    
-    // Robot control settings
-    control_frequency = CONTROL_FREQUENCY;
     
     // Safety settings
     max_linear_velocity = MAX_LINEAR_VELOCITY;