feat(core): format handles for templates

Implement Display for generated Handle<T> values and migrate example view data to carry handles directly instead of raw handle id numbers for dynamic handle attributes.

req: public_api/001

req: public_api/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::{IntoEffect, SafeHtml};
+use slhx::{Handle, IntoEffect, SafeHtml};
 use slhx_axum::{runtime_js, sse, DispatchRejection, EffectResponse, HandlerRegistry, InteractionForm, PageRequest};
 use slhx_kanban_example::ui;
 use std::collections::BTreeMap;
@@ -51,9 +51,9 @@ struct BoardColumn {
 struct BoardCard {
     id: u64,
     title: String,
-    left_handle: u32,
-    right_handle: u32,
-    delete_handle: u32,
+    left_handle: Handle<()>,
+    right_handle: Handle<()>,
+    delete_handle: Handle<()>,
     left_disabled: bool,
     right_disabled: bool,
 }
@@ -292,9 +292,9 @@ fn render_card(card: &Card) -> BoardCard {
     BoardCard {
         id: card.id,
         title: card.title.clone(),
-        left_handle: ui::board::handles::move_left.id().id,
-        right_handle: ui::board::handles::move_right.id().id,
-        delete_handle: ui::board::handles::delete_card.id().id,
+        left_handle: ui::board::handles::move_left,
+        right_handle: ui::board::handles::move_right,
+        delete_handle: ui::board::handles::delete_card,
         left_disabled: card.column == 0,
         right_disabled: card.column + 1 == COLUMNS.len(),
     }