feat: display default options for digest and magic_file plugins

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

src/meta_plugin/magic.rs

@@ -44,6 +44,11 @@ impl MagicFileMetaPlugin {
             .and_then(|v| v.as_u64())
             .unwrap_or(PIPESIZE as u64) as usize;
         
+        // Ensure the default max_buffer_size is in the options
+        if !final_options.contains_key("max_buffer_size") {
+            final_options.insert("max_buffer_size".to_string(), serde_yaml::Value::Number(PIPESIZE.into()));
+        }
+        
         let mut base = crate::meta_plugin::BaseMetaPlugin::new();
         base.outputs = final_outputs;
         base.options = final_options;