test(cli): RED — a missing [nodes] dir leaks the cargo metadata error (#245)

RED pin: a_missing_nodes_pointer_dir_refuses_without_the_cargo_metadata_leak
(project.rs unit tests) — the refusal must name the absent directory and
keep the [nodes] context, with no cargo-metadata wrap.

refs #245

crates/aura-cli/src/project.rs

@@ -622,6 +622,38 @@ mod tests {
         std::fs::remove_dir_all(&tmp).ok();
     }
 
+    /// #245: a `[nodes]` pointer at a directory that does not exist refuses
+    /// with a clean message — it names the missing directory and keeps the
+    /// `[nodes]` pointer context, but does NOT leak the raw `cargo metadata`
+    /// toolchain error. That wrap is reserved for a directory that exists but
+    /// is not a valid crate; a plainly-absent directory should say exactly
+    /// that (`load` still refuses → CLI exit 1).
+    #[test]
+    fn a_missing_nodes_pointer_dir_refuses_without_the_cargo_metadata_leak() {
+        let tmp = std::env::temp_dir().join(format!("aura-missingptr-{}", std::process::id()));
+        std::fs::create_dir_all(&tmp).unwrap();
+        // `missing-node-crate` is never created — the pointer target is absent.
+        std::fs::write(
+            tmp.join("Aura.toml"),
+            "[nodes]\ncrates = [\"missing-node-crate\"]\n",
+        )
+        .unwrap();
+        let e = load(&tmp, false).unwrap_err();
+        let msg = e.to_string();
+        // names the offending pointer path ...
+        assert!(msg.contains("missing-node-crate"), "names the pointer path: {msg}");
+        // ... says plainly that the directory is not there ...
+        assert!(msg.contains("does not exist"), "states the directory is absent: {msg}");
+        // ... keeps the [nodes] pointer context ...
+        assert!(msg.contains("[nodes]"), "keeps the pointer context: {msg}");
+        // ... and does not leak the raw toolchain error for a simple absence.
+        assert!(
+            !msg.contains("cargo metadata"),
+            "no cargo-metadata leak for an absent directory: {msg}"
+        );
+        std::fs::remove_dir_all(&tmp).ok();
+    }
+
     #[test]
     fn aura_toml_parses_empty_partial_and_unknown_keys() {
         let t: AuraToml = toml::from_str("").unwrap();