refac: only show resizer when controls is open

src/lib/components/chat/ChatControls.svelte

@@ -127,11 +127,14 @@
 		{/if}
 	{:else}
 		<!-- if $showControls -->
-		<PaneResizer class="relative flex w-2 items-center justify-center bg-background group">
-			<div class="z-10 flex h-7 w-5 items-center justify-center rounded-sm">
-				<EllipsisVertical className="size-4 invisible group-hover:visible" />
-			</div>
-		</PaneResizer>
+
+		{#if $showControls}
+			<PaneResizer class="relative flex w-2 items-center justify-center bg-background group">
+				<div class="z-10 flex h-7 w-5 items-center justify-center rounded-sm">
+					<EllipsisVertical className="size-4 invisible group-hover:visible" />
+				</div>
+			</PaneResizer>
+		{/if}
 		<Pane
 			bind:pane
 			defaultSize={$showControls