fix: add missing MetaPluginType imports

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

src/meta_plugin/digest.rs

@@ -1,6 +1,6 @@
 use sha2::{Digest, Sha256, Sha512};
 use md5;
-use crate::meta_plugin::MetaPlugin;
+use crate::meta_plugin::{MetaPlugin, MetaPluginType};
 use std::fmt;
 use std::io::Write;