test(techdemo): exercise checked form handler path

Add techdemo coverage for #[slhx::form] plus #[slhx::handler] on the generated launch_work form, and ignore the internal __h hidden handle field in generated form metadata.

req: form/001

req: form/004

req: form/006

req: derive_handler/003

examples/techdemo/src/lib.rs

@@ -5,7 +5,7 @@ pub mod ui {}
 mod tests {
     use super::ui;
     use hemplate::Hemplate;
-    use slhx::{IntoEffect, SafeHtml};
+    use slhx::{Effect, IntoEffect, Payload, SafeHtml};
     use slhx_test::inspect;
 
     #[derive(Hemplate)]
@@ -14,6 +14,15 @@ mod tests {
         label: &'static str,
     }
 
+    #[allow(dead_code)]
+    #[derive(Clone, Debug)]
+    #[slhx::form("launch_work")]
+    struct LaunchWork {
+        title: String,
+        lane: String,
+        impact: Option<u8>,
+    }
+
     // req: examples/001 req: codegen/002 req: public_api/001
     #[test]
     fn techdemo_uses_generated_slots_for_multi_target_updates() {
@@ -38,6 +47,22 @@ mod tests {
         )
     }
 
+    // req: examples/001 req: form/001 req: form/004 req: form/006 req: derive_handler/003
+    #[test]
+    fn techdemo_form_handler_is_checked_against_hemplate_form() {
+        #[slhx::handler]
+        fn launch_work(_form: slhx::Form<LaunchWork>) -> impl IntoEffect {
+            ui::control_center::slots::notice.text("queued")
+        }
+
+        let batch = inspect(launch_work(
+            ui::control_center::forms::launch_work.typed::<LaunchWork>(),
+        ));
+
+        assert!(batch.has_slot(ui::control_center::slots::notice));
+        assert!(matches!(batch.ops(), [Effect::Put { payload: Payload::Text(_), .. }]));
+    }
+
     // req: examples/001 req: form/002 req: codegen/003
     #[test]
     fn techdemo_exports_form_and_interaction_handles() {