feat: enhance strictness of Rust compiler settings and improve code quality by treating warnings as errors

src/app/subagent/context.rs

@@ -2,7 +2,7 @@
 //! including the default read-only tool set for reviewer agents.
 
 use std::path::PathBuf;
-use std::sync::{Arc, Mutex, atomic::{AtomicBool, Ordering}};
+use std::sync::{Arc, Mutex, atomic::AtomicBool};
 use super::spawn::AgentDefinition;
 
 /// Default read-only tool names granted to `role == "reviewer"` agents.