`#[prop(children)]` names the prop that the block between a component's
tags fills. A render-prop slot takes tags lazily, wrapped in a closure so
they are built when the component calls them, and takes a single closure
child straight through when the slot hands over a handle.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017W8YfdzDmZcR8A76jRjvZY