refac: remove redundant overlay with temp chat

src/lib/components/layout/Sidebar.svelte

@@ -647,11 +647,7 @@
 			</div>
 		{/if}
 
-		<div
-			class="relative flex flex-col flex-1 overflow-y-auto overflow-x-hidden {$temporaryChatEnabled
-				? 'opacity-20'
-				: ''}"
-		>
+		<div class="relative flex flex-col flex-1 overflow-y-auto overflow-x-hidden">
 			{#if ($models ?? []).length > 0 && ($settings?.pinnedModels ?? []).length > 0}
 				<div class="mt-0.5">
 					{#each $settings.pinnedModels as modelId (modelId)}
@@ -775,10 +771,6 @@
 					}
 				}}
 			>
-				{#if $temporaryChatEnabled}
-					<div class="absolute z-40 w-full h-full flex justify-center"></div>
-				{/if}
-
 				{#if $pinnedChats.length > 0}
 					<div class="flex flex-col space-y-1 rounded-xl">
 						<Folder