refactor(v0): render todos with hemplate

Move the v0 todo-list payload from Rust raw HTML formatting into a hemplate partial/view and cover both populated and empty rendered structure with scraper.

req: html_safety/002

req: view/001

req: test/005

examples/v0/templates/partials/todo_items.heml

@@ -0,0 +1,6 @@
+<template h-if="self.items.is_empty()">
+  <li>No todos yet</li>
+</template>
+<template h-else>
+  <li h-for="todo in &self.items" +data-key="todo.id">{+ todo.title +}</li>
+</template>