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/runtime.rs

@@ -243,12 +243,23 @@ impl Runtime {
         self: &Arc<Self>,
         component: &Component,
         cfg: InstanceConfig,
+    ) -> Result<Instance> {
+        self.start_with_args(component, cfg, &[]).await
+    }
+
+    /// Start a WASI task with explicit CLI arguments, including its program name.
+    pub async fn start_with_args(
+        self: &Arc<Self>,
+        component: &Component,
+        cfg: InstanceConfig,
+        args: &[String],
     ) -> Result<Instance> {
         let (host_in, guest_in) = tokio::io::duplex(64 * 1024);
         let (guest_out, host_out) = tokio::io::duplex(64 * 1024);
 
         let (guest_err, host_err) = tokio::io::duplex(64 * 1024);
         let mut b = WasiCtx::builder();
+        b.args(args);
         if cfg.network {
             b.inherit_network()
                 .allow_tcp(true)