refactor: cambiar render a slot en AppShell y layouts

Co-authored-by: aider (openrouter/openai/gpt-5) <aider@aider.chat>

apps/web/src/lib/ui/layout/AppShell.svelte

@@ -1,5 +1,4 @@
 <script lang="ts">
-  let { children } = $props();
 </script>
 
 <header class="app-header">
@@ -17,7 +16,7 @@
 </header>
 
 <main class="container main">
-  {@render children?.()}
+  <slot />
 </main>
 
 <style>

apps/web/src/routes/+layout.svelte

@@ -2,8 +2,6 @@
 	import favicon from '$lib/assets/favicon.svg';
 	import '$lib/styles/tokens.css';
 	import '$lib/styles/base.css';
-
-	let { children } = $props();
 </script>
 
 <svelte:head>
@@ -11,4 +9,4 @@
 	<meta name="robots" content="noindex,nofollow" />
 </svelte:head>
 
-{@render children?.()}
+<slot />

apps/web/src/routes/app/+layout.svelte

@@ -1,8 +1,7 @@
 <script lang="ts">
   import AppShell from '$lib/ui/layout/AppShell.svelte';
-  let { children } = $props();
 </script>
 
 <AppShell>
-  {@render children?.()}
+  <slot />
 </AppShell>