fix(core): type slot render payloads

Tighten typed Slot::render and KeyedSlot append/prepend/replace helpers so callers pass the generated slot payload type, keeping explicit html/text escape hatches for deliberate conversions.

req: codegen/002

req: typed_id/001

slhx-core/tests/effect_batch.rs

@@ -11,9 +11,9 @@ fn effect_batch_wire_round_trips() {
     let user = Atom::<String>::new(3);
 
     let batch = (
-        count.text(2),
-        todos.append(7, "Buy milk"),
-        todos.replace(7, "Buy oat milk"),
+        count.render(2),
+        todos.append(7, String::from("Buy milk")),
+        todos.replace(7, String::from("Buy oat milk")),
         user.set("Ada"),
         navigate("/todos"),
         event("toast", "Saved"),
@@ -31,7 +31,8 @@ fn effect_batch_wire_round_trips() {
 #[test]
 fn keyed_slot_replace_uses_scoped_resource_ref() {
     let todos = KeyedSlot::<u64, String>::new(9);
-    let effect = todos.replace(12, "done");
+    // req: codegen/002
+    let effect = todos.replace(12, String::from("done"));
 
     let Effect::Put { target, payload } = effect else {
         panic!("expected Put");