refactor: move binary detection to common module and enhance get logic

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

src/meta_plugin/system.rs

@@ -8,6 +8,7 @@ use std::env;
 use std::process;
 use uzers::{get_current_uid, get_current_gid, get_current_username, get_current_groupname};
 
+use crate::common::is_binary;
 use crate::meta_plugin::MetaPlugin;
 
 #[derive(Debug, Clone, Default)]
@@ -258,7 +259,7 @@ impl MetaPlugin for BinaryMetaPlugin {
     }
 
     fn finalize(&mut self) -> io::Result<String> {
-        let is_binary = Self::is_binary(&self.buffer);
+        let is_binary = is_binary(&self.buffer);
         Ok(if is_binary { "true".to_string() } else { "false".to_string() })
     }