fix: implement debug for meta plugin program and remove unused imports

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

src/meta_plugin.rs

@@ -1,6 +1,5 @@
 use anyhow::Result;
 use std::io;
-use std::io::Write;
 use rusqlite::Connection;
 use log::debug;