fix: remove unused imports and fix settings default error

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/meta_plugin.rs

@@ -116,7 +116,7 @@ pub trait MetaPlugin {
     }
     
     // Configure plugin with options (excluding outputs)
-    fn configure_options(&mut self, options: &std::collections::HashMap<String, serde_yaml::Value>) -> Result<()> {
+    fn configure_options(&mut self, _options: &std::collections::HashMap<String, serde_yaml::Value>) -> Result<()> {
         // Default implementation does nothing - plugins can override this
         Ok(())
     }