Rename input event handler to handle_events

Rename the input event handler module and function.
Update imports, re‑exports, and main.rs to use handle_events.
Add a brief doc comment for the new function.

src/app/threads/mod.rs

@@ -1,5 +1,5 @@
 pub mod events;
-pub mod handle_input_events;
+pub mod handle_events;
 
 pub use events::AppEvent;
-pub use handle_input_events::handle_input_events;
+pub use handle_events::handle_events;