fix: update chevron icon to use Svelte 5 snippet syntax

- Replace slot="icon" with snippet syntax for dropdown chevron button
- Fixes missing chevron icon in Media tab actions dropdown

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/routes/admin/media/+page.svelte

@@ -383,7 +383,9 @@
 			<div class="actions-dropdown">
 				<Button variant="primary" buttonSize="large" onclick={openUploadModal}>Upload</Button>
 				<Button variant="ghost" iconOnly buttonSize="large" onclick={handleDropdownToggle}>
-					<ChevronDown slot="icon" />
+					{#snippet icon()}
+						<ChevronDown />
+					{/snippet}
 				</Button>
 
 				{#if isDropdownOpen}