fix: Fix async runtime mismatch in virtual "wasmer run" command

The virtual "wasmer run" command available in wasix was switched to a
inline waker for resolving the future, but it calls
BinaryPackage::from_registry, which needs to run in a tokio runtime, due
to doing web requests for package retrieval.

Easily fixed by delegating to the main runtime.

Closes #4269

lib/wasix/src/os/command/builtins/cmd_wasmer.rs

@@ -2,7 +2,7 @@ use std::{any::Any, sync::Arc};
 
 use crate::{
     os::task::{OwnedTaskStatus, TaskJoinHandle},
-    runtime::task_manager::InlineWaker,
+    runtime::task_manager::{InlineWaker},
     SpawnError,
 };
 use wasmer::{FunctionEnvMut, Store};
@@ -96,8 +96,15 @@ impl CmdWasmer {
     }
 
     pub async fn get_package(&self, name: &str) -> Result<BinaryPackage, anyhow::Error> {
+        // Need to make sure this task runs on the main runtime.
+        let (tx, rx) = tokio::sync::oneshot::channel();
         let specifier = name.parse()?;
-        BinaryPackage::from_registry(&specifier, &*self.runtime).await
+        let rt = self.runtime.clone();
+        self.runtime.task_manager().task_shared(Box::new(|| Box::pin(async move {
+            let res = BinaryPackage::from_registry(&specifier, rt.as_ref()).await;
+            tx.send(res).expect("could not send response to output channel");
+        })))?;
+        rx.await.map_err(|_| anyhow::anyhow!("package retrieval response channel died"))?
     }
 }