feat: Make FilterChain clonable

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/filter_plugin/mod.rs

@@ -26,6 +26,7 @@ enum FilterType {
     StripAnsi,
 }
 
+#[derive(Clone)]
 pub struct FilterChain {
     plugins: Vec<Box<dyn FilterPlugin>>,
 }