feat(tvix/nix-compat): introduce magic hello/response

Setting the wire module as public to re-use it from tvix-daemon.

Change-Id: I570cffc480c7b784d813663f77572bbe9d4e8259
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11197
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

tvix/nix-compat/src/lib.rs

@@ -5,4 +5,4 @@ pub mod narinfo;
 pub mod nixbase32;
 pub mod nixhash;
 pub mod store_path;
-mod wire;
+pub mod wire;