Add servercom library to make building voltlane servers easier

[lionkor]

Adds a servercom module; used soon in voltchat as a demo.

[Copilot]

Pull Request Overview

This PR introduces a new library “servercom” to simplify constructing voltlane servers and updates the connserver module to adopt new async function signatures without async-trait.

• Added MasterServer trait and ServerCore struct in servercom for handling client connections.
• Updated Cargo.toml workspaces to include the new servercom crate.
• Modified the MasterDuplex trait in connserver to use new async function signatures.

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
servercom/src/lib.rs	Introduces new traits and a core server structure utilizing new async closure patterns.
servercom/Cargo.toml	Defines the new servercom package and its dependencies.
connserver/src/master.rs	Updates MasterDuplex trait to use impl Future return types instead of async_trait.
connserver/Cargo.toml	Removes the dependency on async-trait in favor of new async function syntax.
Cargo.toml	Updates workspace members to include servercom.

Comments suppressed due to low confidence (2)

servercom/src/lib.rs:10

• It is unclear whether AsyncFnMut is a custom trait or imported from a dependency; consider adding documentation or an explicit import to clarify its origin and expected behavior.

        send_packet: impl AsyncFnMut(net::TaggedPacket) -> anyhow::Result<()>,

connserver/src/master.rs:11

• Ensure that the future returned by implementations of send_packet satisfies the Send bound as required by the trait to maintain consistency with asynchronous usage across the codebase.

    fn send_packet(&mut self, packet: TaggedPacket) -> impl Future<Output = anyhow::Result<()>> + Send;