Consolidate event handling into events.rs

The event loop function is now defined in `events.rs`, the redundant
`handle_events.rs` file is removed, and the module re‑exports are
updated
to expose `handle_events` from `events`.

src/app/threads/mod.rs

@@ -1,7 +1,5 @@
 pub mod audio;
 pub mod events;
-pub mod handle_events;
 
 pub use audio::{AudioCmd, SoundrackParts, Soundtrack, handle_audio};
-pub use events::AppEvent;
-pub use handle_events::handle_events;
+pub use events::{AppEvent, handle_events};