cargo.build, the WASI test runner, the console, and core.notify ordering

- cargo.build (native): one source copy, tests under WASI, release
  build to /state/cargo/builds/<n>/, process groups killed on cancel.
  The host writes the SDK copy to /plugins/cargo/sdk/ at start.
- sausage test-runner: one instance per test, in parallel, with its own
  mount table (empty world, package folder at its path); answers
  core.lock, core.unlock, core.notify, core.log.
- The console: rustyline, notifications while typing, ls/cat through the
  process view, methods, ps, log, activate, revert, stop, kill.
- core.notify on stdout is handled in order, before the response.

cli/src/main.rs

@@ -4,6 +4,7 @@ use clap::{Parser, Subcommand};
 use sausage::{Host, world::World};
 use serde_json::json;
 use std::{io::Write, path::PathBuf};
+mod test_runner;
 #[derive(Parser)]
 #[command(version)]
 struct Cli {
@@ -16,8 +17,18 @@ struct Cli {
 }
 #[derive(Subcommand)]
 enum Cmd {
-    Init { dir: PathBuf },
-    Run { dir: PathBuf },
+    Init {
+        dir: PathBuf,
+    },
+    Run {
+        dir: PathBuf,
+    },
+    /// Run a WASI libtest component in isolated instances.
+    TestRunner {
+        wasm: PathBuf,
+        #[arg(trailing_var_arg = true, allow_hyphen_values = true)]
+        args: Vec<String>,
+    },
 }
 fn setting(var: &str, question: &str, default: Option<&str>) -> Result<String> {
     if let Ok(v) = std::env::var(var)
@@ -41,6 +52,11 @@ fn setting(var: &str, question: &str, default: Option<&str>) -> Result<String> {
 async fn main() -> Result<()> {
     let cli = Cli::parse();
     match cli.command {
+        Cmd::TestRunner { wasm, args } => {
+            if !test_runner::run(&wasm, args).await? {
+                std::process::exit(1);
+            }
+        }
         Cmd::Init { dir } => {
             let api = setting("SAUSAGE_API", "API shape", Some("openai-responses"))?;
             if api != "openai-responses" && api != "anthropic-messages" {
@@ -65,10 +81,12 @@ async fn main() -> Result<()> {
                 None => Host::start(&dir).await?,
             };
             let mut notifications = host.subscribe();
-            let notification_task = tokio::spawn(async move {
-                while let Ok(notification) = notifications.recv().await {
-                    println!("{notification}");
-                }
+            let notification_task = cli.headless.then(|| {
+                tokio::spawn(async move {
+                    while let Ok(notification) = notifications.recv().await {
+                        println!("{notification}");
+                    }
+                })
             });
             let console = sausage::console::run_input(host.clone());
             let exit = tokio::select! {
@@ -82,7 +100,9 @@ async fn main() -> Result<()> {
             };
             let exit = exit || host.restart_requested();
             host.stop().await;
-            notification_task.abort();
+            if let Some(task) = notification_task {
+                task.abort();
+            }
             if exit {
                 std::process::exit(75);
             }