refactor: flatten module structure, remove threads directory [3/8]

Move files from tasks/ to root and remove threads/ directory:
- concurrency/src/tasks/* → concurrency/src/*
- Delete concurrency/src/threads/ (replaced by Backend enum)
- Update all imports from spawned_concurrency::tasks:: to spawned_concurrency::

The Backend enum (Async, Blocking, Thread) now provides all the
functionality previously split between tasks and threads modules,
offering a cleaner and more unified API.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: unbalancedparentheses

concurrency/src/tasks/gen_server.rs concurrency/src/gen_server.rsconcurrency/src/tasks/gen_server.rs renamed to concurrency/src/gen_server.rs

@@ -1,9 +1,7 @@
 //! GenServer trait and structs to create an abstraction similar to Erlang gen_server.
 //! See examples/name_server for a usage example.
-use crate::{
-    error::GenServerError,
-    tasks::InitResult::{NoSuccess, Success},
-};
+use crate::error::GenServerError;
+use InitResult::{NoSuccess, Success};
 use core::pin::pin;
 use futures::future::{self, FutureExt as _};
 use spawned_rt::{
@@ -480,7 +478,7 @@ mod warn_on_block {
 mod tests {
 
     use super::*;
-    use crate::{messages::Unused, tasks::send_after};
+    use crate::{messages::Unused, send_after};
     use std::{
         sync::{Arc, Mutex},
         thread,

concurrency/src/lib.rs

@@ -1,6 +1,22 @@
 //! spawned concurrency
 //! Some basic traits and structs to implement concurrent code à-la-Erlang.
 pub mod error;
+mod gen_server;
 pub mod messages;
-pub mod tasks;
-pub mod threads;
+mod process;
+mod stream;
+mod time;
+
+#[cfg(test)]
+mod stream_tests;
+#[cfg(test)]
+mod timer_tests;
+
+pub use error::GenServerError;
+pub use gen_server::{
+    send_message_on, Backend, CallResponse, CastResponse, GenServer, GenServerHandle,
+    GenServerInMsg, InitResult, InitResult::NoSuccess, InitResult::Success,
+};
+pub use process::{send, Process, ProcessInfo};
+pub use stream::spawn_listener;
+pub use time::{send_after, send_interval};

concurrency/src/tasks/process.rs concurrency/src/process.rsconcurrency/src/tasks/process.rs renamed to concurrency/src/process.rs

@@ -1,4 +1,4 @@
-use crate::tasks::{GenServer, GenServerHandle};
+use crate::{GenServer, GenServerHandle};
 use futures::{future::select, Stream, StreamExt};
 use spawned_rt::tasks::JoinHandle;
 

concurrency/src/tasks/stream.rs concurrency/src/stream.rsconcurrency/src/tasks/stream.rs renamed to concurrency/src/stream.rs

@@ -1,6 +1,5 @@
-use crate::tasks::{
-    send_after, stream::spawn_listener, Backend, CallResponse, CastResponse, GenServer,
-    GenServerHandle,
+use crate::{
+    send_after, spawn_listener, Backend, CallResponse, CastResponse, GenServer, GenServerHandle,
 };
 use futures::{stream, StreamExt};
 use spawned_rt::tasks::{self as rt, BroadcastStream, ReceiverStream};