ref: state - 2 (#4229)

Extracting tasks in a module and start abstraction behind a Trait (more
to come on this but each task will be tackled in a dedicated PR)
The goal was to drop the ActiveTask and to have a (potentially) set of
tasks during each turn

codex-rs/core/tests/suite/mod.rs

@@ -1,5 +1,7 @@
 // Aggregates all former standalone integration tests as modules.
 
+#[cfg(not(target_os = "windows"))]
+mod abort_tasks;
 mod cli_stream;
 mod client;
 mod compact;