Mount the writable world root for every actor

cli/src/world.rs

@@ -3,13 +3,14 @@
 //! watches the folder (`watch.rs`).
 //!
 //! ```text
-//! <world>/
+//! <world>/              mounted at /, readable and writable by every actor
+//!   config/             global configuration by convention (no secrets)
 //!   actor/<id>/
 //!     actor.wasm        the current version
 //!     actor.json        version, running, subscriptions, tapped, watches (broker)
 //!     source/           source of the current version
-//!     public/           written by the actor, read-only for others
-//!     data/             state, writable only by the actor
+//!     public/           published files, readable and writable by everyone
+//!     data/             state, readable and writable by everyone
 //!     stderr.log        stderr of the actor and notes of the broker
 //!     versions/<n>/     every version that was installed: actor.wasm, source/, meta.json
 //! ```
@@ -131,6 +132,7 @@ impl World {
         for id in NATIVE {
             world.ensure_actor_dirs(id)?;
         }
+        std::fs::create_dir_all(world.root.join("config"))?;
         Ok(world)
     }
 
@@ -191,8 +193,8 @@ impl World {
 
     /// Map a path in an actor's namespace to a host path.
     ///
-    /// - `/actor/<id>/...` is the global filesystem.
-    /// - `/public/...` and `/data/...` belong to `sender`.
+    /// - Absolute paths are relative to the world root.
+    /// - `/public/...` and `/data/...` alias `sender`'s folders.
     /// - Native senders (the console) can also give absolute host paths.
     pub fn resolve(&self, sender: &str, path: &str) -> Result<PathBuf> {
         let under = |base: PathBuf, rest: &str| -> Result<PathBuf> {
@@ -221,13 +223,16 @@ impl World {
         if NATIVE.contains(&sender) && Path::new(path).is_absolute() {
             return Ok(PathBuf::from(path));
         }
-        bail!("cannot resolve path {path} for {sender}: use /actor/<id>/..., /public/... or /data/...")
+        if Path::new(path).is_absolute() {
+            return under(self.root.clone(), path);
+        }
+        bail!("cannot resolve path {path} for {sender}: use an absolute world path")
     }
 
     /// The path of a host file in the global filesystem, if it has one.
     pub fn global_path(&self, host: &Path) -> Option<String> {
-        let rel = host.strip_prefix(self.actors_root()).ok()?;
-        Some(format!("/actor/{}", rel.display()))
+        let rel = host.strip_prefix(&self.root).ok()?;
+        Some(format!("/{}", rel.display()))
     }
 }