feat(slhx): render hemplate views into slots

Add render_html plus slot render_view helpers that call hemplate render_into, and migrate a kanban effect path from explicit SafeHtml/html handling to the renderable-view helper.

req: view/001

req: html_safety/002

examples/kanban/src/main.rs

@@ -4,7 +4,7 @@ use axum::routing::get;
 use axum::Router;
 use futures_util::{stream, StreamExt};
 use hemplate::Hemplate;
-use slhx::{Handle, IntoEffect, SafeHtml};
+use slhx::{Handle, IntoEffect, RenderSlotExt, SafeHtml};
 use slhx_axum::{runtime_js, sse, DispatchRejection, EffectResponse, HandlerRegistry, InteractionForm, PageRequest};
 use slhx_kanban_example::ui;
 use std::collections::BTreeMap;
@@ -131,13 +131,13 @@ async fn interact(
 // req: push/001 req: push/003 req: examples/001
 async fn events(Query(params): Query<BTreeMap<String, String>>) -> impl IntoResponse {
     if params.contains_key("once") {
-        let effect = ui::board::slots::presence.html(render_presence(1));
+        let effect = ui::board::slots::presence.render_view(&Presence { count: 1 });
         return sse(stream::iter([Ok::<_, Infallible>(effect.into_batch(ui::BUILD_FINGERPRINT))]).boxed());
     }
 
     let batches = stream::unfold(1_u64, |count| async move {
         tokio::time::sleep(Duration::from_secs(4)).await;
-        let effect = ui::board::slots::presence.html(render_presence(count));
+        let effect = ui::board::slots::presence.render_view(&Presence { count });
         Some((Ok::<_, Infallible>(effect.into_batch(ui::BUILD_FINGERPRINT)), count + 1))
     })
     .boxed();
@@ -199,7 +199,7 @@ fn registry(state: Arc<AppState>) -> HandlerRegistry {
 
 fn board_effects(board: &BoardState, notice: &'static str) -> impl IntoEffect {
     (
-        ui::board::slots::board.html(render_board(board)),
+        ui::board::slots::board.render_view(&board_view(board)),
         ui::board::slots::notice.text(notice),
         ui::board::forms::create_card.clear("title"),
     )
@@ -269,9 +269,9 @@ fn render_options() -> SafeHtml {
     })
 }
 
-fn render_board(board: &BoardState) -> SafeHtml {
+fn board_view(board: &BoardState) -> BoardColumns {
     // req: html_safety/002 req: view/001
-    render_html(&BoardColumns {
+    BoardColumns {
         columns: COLUMNS
             .iter()
             .enumerate()
@@ -285,7 +285,12 @@ fn render_board(board: &BoardState) -> SafeHtml {
                     .collect(),
             })
             .collect(),
-    })
+    }
+}
+
+fn render_board(board: &BoardState) -> SafeHtml {
+    // req: html_safety/002 req: view/001
+    render_html(&board_view(board))
 }
 
 fn render_card(card: &Card) -> BoardCard {
@@ -300,11 +305,6 @@ fn render_card(card: &Card) -> BoardCard {
     }
 }
 
-fn render_presence(count: u64) -> SafeHtml {
-    // req: html_safety/002 req: view/001
-    render_html(&Presence { count })
-}
-
 fn render_html(template: &impl Hemplate) -> SafeHtml {
     SafeHtml::trusted(render_template(template))
 }
@@ -368,7 +368,7 @@ mod tests {
     // req: html_safety/002 req: view/001 req: test/005
     #[test]
     fn presence_payload_is_rendered_by_a_hemplate_view() {
-        let html = render_presence(7);
+        let html = render_html(&Presence { count: 7 });
         let document = Html::parse_fragment(html.as_str());
         assert_eq!(document.select(&selector("span.presence")).count(), 2);
         assert_eq!(