builder: add native Cargo service and world CLI

host/src/api/mod.rs

@@ -1,6 +1,8 @@
 //! JSON routes for host.sausage. The transport supplies the trusted caller.
 //! Host-owned pages use passkeys and typed proofs for every authorization ceremony.
 mod auth;
+mod cargo;
+pub(crate) use cargo::stream;
 mod pages;
 mod server;
 mod ssh;
@@ -19,6 +21,7 @@ use std::{
 
 pub struct Api {
     pub cred: Arc<Cred>,
+    pub(crate) builder: std::sync::OnceLock<Arc<crate::builder::Builder>>,
     script: cred::quickjs::QuickJs,
     pub passkeys: Mutex<Passkeys<rusqlite::Connection>>,
     pub entry: EntryKey,
@@ -47,6 +50,7 @@ impl Api {
     ) -> Self {
         Self {
             cred: cred.into(),
+            builder: Default::default(),
             script: cred::quickjs::QuickJs::default(),
             passkeys: Mutex::new(passkeys),
             entry,