test(cli): RED — scaffold's starter node must read a bound param (#183)

The `aura new` scaffold ships one node, a param-less Identity, so there is
no public example of a build closure consuming a bound param — the F2 gap
the project-environment fieldtest rated its highest-value authoring miss.
This pins the target: the rendered starter lib.rs declares a ParamSpec and
reads p[0] in its build closure, and the starter blueprint binds `factor`
on the project's own node, so `aura run` exercises the bound-param path
with zero hand-editing.

refs #183

crates/aura-cli/src/scaffold.rs

@@ -321,6 +321,37 @@ mod tests {
         assert!(cargo.contains("/crates/aura-core"));
     }
 
+    /// Property (#183, fieldtest F2 gap): the scaffold's own starter node teaches
+    /// the bound-param build closure. Its rendered `src/lib.rs` declares a param in
+    /// the node schema and reads a bound value in the build closure (not the
+    /// param-less `|_|` Identity the template shipped before), and the rendered
+    /// starter blueprint binds `factor` on the project's own node — so `aura run`
+    /// exercises the bound-param path with zero hand-editing. (The scaffold→build→
+    /// run e2e in tests/project_new.rs re-validates the swap end to end; this pins
+    /// the copyable template content a newcomer learns from directly.)
+    #[test]
+    fn starter_node_declares_and_reads_a_bound_param() {
+        let spec = spec_for("demo-lab", None);
+        let lib = render(LIB_RS, &spec);
+        // (a) the node schema declares a bindable param...
+        assert!(
+            lib.contains("ParamSpec"),
+            "starter node must declare a param in its schema, not `params: vec![]`: {lib}"
+        );
+        // ...and the build closure reads that bound param (p[0]), not `|_|`.
+        assert!(
+            lib.contains("p[0].f64()"),
+            "starter build closure must consume a bound param (p[0].f64()), not `|_|`: {lib}"
+        );
+        // (b) the starter blueprint binds `factor` on the project's own node, so
+        // `aura run` drives the bound-param path out of the box.
+        let json = render(SIGNAL_JSON, &spec);
+        assert!(
+            json.contains("\"name\":\"factor\""),
+            "starter blueprint must bind the `factor` param on the project node: {json}"
+        );
+    }
+
     #[test]
     fn scaffold_refuses_existing_dir_and_missing_engine() {
         let tmp = std::env::temp_dir().join(format!("aura-scaf-{}", std::process::id()));