fix: adjust z-index for CodeBlock component and update ChatInput max height for better responsiveness

src/lib/components/CodeBlock.svelte

@@ -32,7 +32,7 @@
 </script>
 
 <div class="group relative my-4 rounded-lg">
-	<div class="pointer-events-none sticky top-0 z-10 w-full">
+	<div class="pointer-events-none sticky top-0 w-full">
 		<div
 			class="pointer-events-auto absolute right-2 top-2 flex items-center gap-1.5 md:right-3 md:top-3"
 		>

src/lib/components/chat/ChatInput.svelte

@@ -99,7 +99,7 @@
 		rows="1"
 		tabindex="0"
 		inputmode="text"
-		class="scrollbar-custom max-h-[4lh] w-full resize-none overflow-y-auto overflow-x-hidden border-0 bg-transparent px-2.5 py-2.5 outline-none focus:ring-0 focus-visible:ring-0 sm:px-3"
+		class="scrollbar-custom max-h-[4lh] w-full resize-none overflow-y-auto overflow-x-hidden border-0 bg-transparent px-2.5 py-2.5 outline-none focus:ring-0 focus-visible:ring-0 sm:px-3 md:max-h-[8lh]"
 		class:text-gray-400={disabled}
 		bind:value
 		bind:this={textareaElement}