refactor(document): remove statusLabel() alias, use formatDocumentStatus directly

statusLabel() was a one-line alias for formatDocumentStatus() with no
additional behaviour. Remove it and update DocumentStatusChip.svelte to
call formatDocumentStatus() directly. Remove the corresponding alias
test suite from the spec file.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/document/DocumentStatusChip.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
 import {
+	formatDocumentStatus,
 	statusDotClass,
-	statusLabel,
 	type DocumentStatus
 } from '$lib/document/documentStatusLabel';
 
@@ -12,7 +12,7 @@ type Props = {
 let { status }: Props = $props();
 
 const dotClass = $derived(statusDotClass(status));
-const label = $derived(statusLabel(status));
+const label = $derived(formatDocumentStatus(status));
 </script>
 
 <span