EXPERIMENT: mesh/pal: Use async_channel instead of futures::channel

[smalis-msft]

We generally believe that async_channel has better performance characteristics than futures channels, but the semantics are slightly different. Let's see what happens here.

Also move one channel in netvsp from futures to mesh, since it was unbounded and doesn't need any of futures' semantics.

[github-actions]

⚠️ Unsafe Code Detected

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[Copilot]

Pull request overview

This experimental PR migrates from futures::channel to async_channel across the mesh and pal subsystems to potentially improve performance characteristics. The changes replace oneshot channels with bounded(1) channels and unbounded mpsc channels with async_channel equivalents.

Key changes:

• Replace futures::channel::oneshot with async_channel::bounded(1)
• Replace futures::channel::mpsc::unbounded with async_channel::unbounded
• Update method calls from unbounded_send() to send_blocking() or send().await

Critical compilation issues identified:

• async_channel::Receiver does not implement the Stream trait, causing compilation failures where .next() or .poll_next() are called on receivers
• Two locations affected: alpc_node.rs line 233 and existing code dependent on changes in local_node.rs line 2494

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Cargo.toml	Removes futures-channel workspace dependency
Cargo.lock	Updates dependencies: adds async-channel to mesh_node, mesh_remote, and pal_uring
support/mesh/mesh_node/Cargo.toml	Replaces futures-channel with async-channel dependency
support/mesh/mesh_node/src/local_node.rs	Replaces oneshot and mpsc channels with async_channel; adds explicit close() call for shutdown signaling
support/mesh/mesh_remote/Cargo.toml	Adds async-channel dependency
support/mesh/mesh_remote/src/alpc_node.rs	Converts mpsc::unbounded to async_channel with Stream usage that won't compile
support/mesh/mesh_remote/src/unix_node.rs	Converts mpsc channels to async_channel; changes send operations from non-blocking to async
support/pal/pal_async/src/executor_tests.rs	Converts oneshot test channels to bounded(1) async_channel
support/pal/pal_uring/Cargo.toml	Adds async-channel as dev-dependency
support/pal/pal_uring/src/threadpool.rs	Converts test oneshot channels to bounded(1) async_channel