refactor(documents): collapse redundant span nesting in DocumentDate else branch

The dated branch wrapped {label} in a flex span containing a single child
span — redundant nesting. Render the label directly in one span.

Refs #668

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/lib/document/DocumentDate.svelte

@@ -59,9 +59,7 @@ const showRawLine = $derived(
 			{label}
 		</span>
 	{:else}
-		<span class="inline-flex items-center gap-1">
-			<span>{label}</span>
-		</span>
+		<span>{label}</span>
 	{/if}
 	{#if showRawLine}
 		<!-- Visible secondary line (WCAG 1.4.13 — not tooltip-only). raw is untrusted