feat(api): streamline generated app authoring

Move the canonical examples toward generated component-root helpers, typed form decoding, async/state handler registration, and derive-driven app/component registry wiring. Tighten requirements and diagnostics for the server-first, selectorless authoring path.

Verified with cargo run -p slhx-xtask -- test, cargo check --workspace, redgate list, redgate refs, redgate health --strict, and git diff --check.

req: canonical/001

req: canonical/003

req: canonical/004

req: dx/002

req: derive_app/001

req: component/003

req: form/004

req: axum_integration/003

slhx-core/tests/effect_batch.rs

@@ -28,6 +28,16 @@ fn effect_batch_wire_round_trips() {
     assert!(decoded.is_compatible());
 }
 
+#[test]
+fn optional_effects_compose_into_batches() {
+    // req: component/005 req: public_api/003
+    let count = Slot::<u32>::new(1);
+    let batch = (Some(count.text(2)), Option::<Effect>::None).into_batch(BuildFingerprint(42));
+
+    assert_eq!(batch.ops.len(), 1);
+    assert_eq!(batch.ops[0], count.text(2));
+}
+
 #[test]
 fn keyed_slot_replace_uses_scoped_resource_ref() {
     let todos = KeyedSlot::<u64, String>::new(9);
@@ -142,7 +152,10 @@ fn generated_css_classes_join_for_hemplate_dynamic_class_attrs() {
     assert_eq!(classes.as_str(), "work-card is-selected");
     assert_eq!(classes.to_string(), "work-card is-selected");
     assert_eq!(CARD.with(SELECTED).as_str(), "work-card is-selected");
-    assert_eq!(CARD.with_if(true, SELECTED).as_str(), "work-card is-selected");
+    assert_eq!(
+        CARD.with_if(true, SELECTED).as_str(),
+        "work-card is-selected"
+    );
     assert_eq!(CARD.with_if(false, SELECTED).as_str(), "work-card");
 }