[hyperactor] mesh: v0 shims for v1 meshes

Pull Request resolved: #1453

In this change, we implement:

```
From<v1::ProcMeshRef> for ProcMesh
```

and

```
From<v1::ActorMeshRef<A>> for RootActorMesh<A>
```

This will allow us to temporarily use v1 instances through a v0 API, while we transition the usage sites.
ghstack-source-id: 314644713

Differential Revision: [D84081478](https://our.internmc.facebook.com/intern/diff/D84081478/)

**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D84081478/)!

Author: mariusae

hyperactor_mesh/src/actor_mesh.rs

@@ -199,11 +199,13 @@ mod tests {
             })
             .await
             .unwrap();
+        let instance = crate::v1::testing::instance().await;
 
         let proc_mesh = ProcMesh::allocate(alloc).await.unwrap();
 
         let handle = hyperactor::simnet::simnet_handle().unwrap();
-        let actor_mesh: RootActorMesh<TestActor> = proc_mesh.spawn("echo", &()).await.unwrap();
+        let actor_mesh: RootActorMesh<TestActor> =
+            proc_mesh.spawn(&instance, "echo", &()).await.unwrap();
         let actors = actor_mesh.iter_actor_refs().collect::<Vec<_>>();
         assert_eq!(
             handle.sample_latency(

hyperactor_mesh/src/alloc/sim.rs

@@ -830,9 +830,9 @@ mod tests {
         let params = TestActorParams {
             forward_port: tx.bind(),
         };
-        let actor_mesh = proc_mesh
-            .clone()
-            .spawn::<TestActor>(dest_actor_name, &params)
+        let instance = crate::v1::testing::instance().await;
+        let actor_mesh = Arc::clone(&proc_mesh)
+            .spawn::<TestActor>(&instance, dest_actor_name, &params)
             .await
             .unwrap();
 
@@ -968,7 +968,7 @@ mod tests {
         } = setup_mesh::<NoneAccumulator>(None).await;
         let proc_mesh_client = actor_mesh.proc_mesh().client();
 
-        let ranks = actor_mesh.ranks.clone();
+        let ranks = actor_mesh.ranks().clone();
         execute_cast_and_reply(ranks, proc_mesh_client, reply1_rx, reply2_rx, reply_tos).await;
     }
 
@@ -1032,7 +1032,7 @@ mod tests {
             ..
         } = setup_mesh(Some(accum::sum::<u64>())).await;
         let proc_mesh_client = actor_mesh.proc_mesh().client();
-        let ranks = actor_mesh.ranks.clone();
+        let ranks = actor_mesh.ranks().clone();
         execute_cast_and_accum(ranks, proc_mesh_client, reply1_rx, reply_tos).await;
     }