refactor(protocol): extract transport module to oxidized-transport crate

Remove transport/ module from oxidized-protocol. The protocol crate
now depends on oxidized-transport and re-exports it as
`pub use oxidized_transport as transport` for backward compatibility.

All downstream imports (oxidized_protocol::transport::*) continue
to work unchanged. All 1,267+ tests pass.

Phase 6 — Transport extraction.

Author: dodoflix

Cargo.lock

@@ -20,6 +20,7 @@ oxidized-auth = { workspace = true }
 oxidized-codec = { workspace = true }
 oxidized-mc-types = { workspace = true }
 oxidized-chat = { workspace = true }
+oxidized-transport = { workspace = true }
 
 tokio        = { workspace = true }
 tokio-util   = { workspace = true }

crates/oxidized-protocol/Cargo.toml

@@ -9,4 +9,6 @@ pub mod constants;
 pub mod packets;
 pub mod registry;
 pub mod status;
-pub mod transport;
+
+// Re-export extracted transport crate for backward compatibility.
+pub use oxidized_transport as transport;