feat(build): add lower-aware put helper

Generate ui::put(slot, view) for lower-aware slot HTML updates and move examples/docs/contracts to that ergonomic path instead of hand-composing slot.html(render(...)).

req: dx/006

req: component/003

req: runtime/001

req: examples/003

examples/v0/src/main.rs

@@ -145,7 +145,7 @@ fn registry(state: Arc<ExampleState>) -> impl DispatchRegistry {
                     todos.push(Todo { id, title: title.into() });
                 }
                 (
-                    todo_slots::todo_list.html(ui::render(&todos_view(&todos))),
+                    todos::put(todo_slots::todo_list, &todos_view(&todos)),
                     todo_forms::new_todo.clear("title"),
                 )
             }
@@ -172,9 +172,9 @@ fn registry(state: Arc<ExampleState>) -> impl DispatchRegistry {
         .on(page_handles::load_docs, |_| {
             // req: page_swap/002, req: examples/001
             (
-                page_slots::content.html(ui::render(&DocsContent {
+                page_swap::put(page_slots::content, &DocsContent {
                     message: "This content came from an EffectBatch.",
-                })),
+                }),
                 page_slots::title.text("Docs"),
                 push("/docs"),
             )